JP6504337B2 - Storage system, storage device, and staging method - Google Patents

Description

  The present invention relates to a storage system, and more particularly to a storage system having a storage area for storing data and a cache area, a storage apparatus, and a staging method.

In recent years, the configuration of computer systems has been greatly changed.
Many computers are connected by a network, storage capacity is increasing, and virtualization technology is also spreading. For example, in data centers that build servers on the cloud, it is also practiced to provide users with virtual operating systems (OSs) and programs using virtualization technology, and manage personal data of users. In addition, the amount of processing operation and data volume handled by thin client systems etc. have increased dramatically.

  The service provider needs to prepare computer system equipment of appropriate scale every time. If the amount of equipment tends to be insufficient, the user's convenience is greatly impeded. On the other hand, if you have extra equipment, it also leads to extra costs for the user.

  Recently, although there are various factors, the amount of computation and storage cost per CPU (Central Processing Unit) and storage device are decreasing. It is expected that the reduction will continue in the future. On the other hand, although the service provider appropriately scales the equipment at each time, preparing the equipment according to the peak will always have surplus equipment. For example, it is difficult to prepare equipment based on a peak as in the following case.

  One case is a peak by one user. In a thin client system that provides a virtual PC (Personal Computer) (virtual desktop) to a user (user terminal), a large amount of computation and data transfer occur in the server system when the user logs in to the server. In other words, a high load condition occurs on the server triggered by the login of the user.

  Another example is a peak by multiple users. Near the opening hours of a company, many users log in to the server simultaneously. This results in a great deal of computation and data transfer occurring in the server system. In other words, a high load condition occurs in the server triggered by the arrival of a certain time.

  Although the amount of data transfer (the amount of communication) between the client terminal and the server needs attention, the amount of data transfer in the server system also needs attention in system construction.

  Similar problems also occur in data centers and internal servers that are not thin client systems. It is necessary to pay attention to the amount of data transfer in a data center or in an in-house server when receiving a request for causing a large number of high load conditions simultaneously. For example, when a data group on the same physical disk receives an acquisition request from many PCs, a high load state occurs in the control system and transfer system that manage the disk.

  These problems are recognized as problems in words such as login storm and boot storm. Also, simultaneous virus checks and updates of clients may cause data processing storms.

  In the current storage system, the reading speed and the writing speed from the storage device can be considered as one factor causing other processing delay factors. That is, there are many cases where the storage device becomes a system bottleneck.

As a prior art relevant to this invention, the staging method described in patent document 1 and patent document 2 is mentioned, for example.
In Patent Document 1, in preparation for the login of each user in a system having many users, the login time of each user is predicted from the time when each user passes through the entrance gate, and the login time of each user is Before We disclose the technology for staging the login information of the user in advance in a cache.
In Patent Document 2, predetermined data to be accessed from a host computer in a specific time zone is set in advance, and the predetermined data is moved from the magnetic disk drive to the cache memory in advance and called from the cache memory when accessing the predetermined data. Technology is disclosed.

JP, 2009-93512, A Unexamined-Japanese-Patent No. 11-259363 gazette

  The concentration of data processing that occurs in the storage system, that is, the storm, improves the reading speed of the storage apparatus, and further improves the existing method for solving the problem.

  The problems of the existing method are summarized below.

1. Ensuring sufficient specifications by appropriate sizing of storage devices
Measures: Perform sizing to sufficient specifications (computing resources, storage capacity, transfer rate securing, etc.) in advance against temporary loads assumed in operation.
Problem: A large amount of expensive memory and solid state disk (SSD) are required to cope with a load that occurs in a short time such as a login storm, which is costly.

2. Method described in Patent Document 1 (staging of login information to cache by time prediction based on gate passage timing)
Countermeasure: The management server predicts the login time of each user from the time when each user passes through the entrance gate, and stages the login information of the corresponding user in the cache memory before the login time of each user.
Problem: If the number of users logging in at the same time is large, a large amount of cache memory is required for staging login information. In addition, cache memory may be occupied by login information, or may overflow from a large amount of login information.

3. Speeding up the storage area by tiering in the storage device
Countermeasures: Necessary data is moved sequentially between high performance SSDs that are layered and HDDs (Hard Disk Drives) that are low cost.
Problem: By responding to requests to temporarily generate a high load state, data movement is frequently performed between the SSD and the HDD. As a result, a large amount of data transfer load occurs in the storage device.

4. Acceleration of storage system by second-level cache
Measures: Use SSD or semiconductor memory as secondary cache of storage device.
Problem: In the case of many disk accesses such as one-time login, etc., it is overwritten before hitting the cache data stored in the secondary cache.

The prior arts disclosed in Patent Document 1 and Patent Document 2 also improve the reading speed of the storage device by staging to cache to improve the problem.
On the other hand, there are various requirements for properly performing the functions of each method. For example, the method disclosed in Patent Document 1 requires the user to pass through a specific gate in advance.
In the method disclosed in Patent Document 2, it is necessary to artificially set in advance the time of staging and predetermined data.

  Thus, unless the various requirements are met, the functions of each method can not be demonstrated effectively. In addition, in response to a request received from a host or the like, it may be difficult for the administrator to know the appropriateness of data extracted as a response.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a storage system, a storage device, and a staging method for efficiently processing a storm of data processing generated in the system from the viewpoint of cost and performance.

The storage system according to the present invention comprises a host for sending out a predetermined request for reading various data, interface means for reading out predetermined data recorded in response to the predetermined request for reading out various data from the host, and a cache area for storing data, a storage area for storing various data including the predetermined data in the data storage area, a storage having, while managing conditions 1 to a plurality of predetermined request occurs as each trigger Means of duplicating predetermined data groups pre-expanded in the cache area for each trigger, from the data storage area to the read standby area provided in the storage area as load data for each of the triggers When, during or just before a respective trigger the respective, Viewed contains a means for expanding the load data corresponding to the trigger from the read waiting area in the cache area, and the read standby region, the storage virtualization, reading standby logical areas and read standby physical area for Garbage data that both are provided and manages load data for each block in units of blocks for load data for each trigger to be recorded in the read standby logical area, and it is determined that expansion to the cache area is unnecessary Further comprising means for deleting data blocks of
Further, a storage system according to the present invention comprises a host for sending out a predetermined request for reading various data, and an interface unit corresponding to reading of predetermined data recorded in response to the predetermined request for reading out various data from the host. A storage area having a cache area for storing various data, and a storage area storing various data including the predetermined data in the data storage area, and managing conditions under which one or more predetermined requests occur as respective triggers While copying a predetermined data group pre-expanded in the cache area for each trigger, from the data storage area to the read standby area provided in the storage area as load data for each of the triggers Means, and when or when each of the respective triggers occur. And means for expanding load data corresponding to each trigger from the read standby area to the cache area, wherein the read standby area is a storage area for read standby logical area and read standby physical by storage virtualization. Both of the areas are provided respectively, and for load data for each trigger recorded in the read standby logical area, each load data is managed in block units, and it is determined that expansion to the cache area is unnecessary. The apparatus further comprises means for extracting data blocks of garbage data and aligning and recording the remaining data blocks in the read standby logical area.

In addition, the storage apparatus according to the present invention includes various means including interface means corresponding to reading of predetermined data recorded, a cache area for storing various data, and the predetermined data in response to a predetermined request for reading various data. a storage area storing the data in the data storage area, 1 or while managing conditions in which a plurality of predetermined request occurs as each trigger, the predetermined data group pre-expanded in the cache area for each of the trigger, the It means for replicating from the data storage area as a respective load data for each respective trigger reading standby region provided in the storage area, at or immediately before the occurrence of each trigger of the respective, corresponding to each trigger developed in the cache area was load data from the read waiting area Possess means that, the, the read standby region, the storage virtualization, both logical area and read standby physical area for reading stand is provided respectively, the trigger for recording the read standby logic area The apparatus is characterized by further comprising means for managing each load data in units of blocks for each load data, and deleting data blocks of garbage data determined to be unnecessary to expand in the cache area .

The staging method in the storage apparatus according to the present invention comprises interface means corresponding to reading of predetermined data recorded in response to a predetermined request for reading various data, a cache area for storing various data, and the predetermined data. a storage device having a storage area which is stored in the data storage area of various data including, as a reading standby region, the storage virtualization, both logical area and read standby physical area for reading standby respectively provided cage, while managing conditions 1 to a plurality of predetermined request occurs as each trigger, the predetermined data group pre-expanded in the cache area for each trigger, as each of the load data for each of the respective trigger Provided in the storage area from the data storage area A step of duplicating the read standby area that is, upon the occurrence of each trigger wherein each or just before, the steps of deploying a load data corresponding to each trigger from the read waiting area in the cache area, the read Managing load data in units of blocks with respect to load data for each trigger recorded in the standby logical area, and deleting data blocks of garbage data determined to be unnecessary to be expanded in the cache area; It is characterized in that it is included in the staging process and executed .
Further, according to a staging method in a storage apparatus according to the present invention, an interface unit corresponding to reading of predetermined data recorded in response to a predetermined request for reading various data, a cache area for storing various data, and A storage apparatus having storage areas in which various data including predetermined data are stored in a data storage area is provided as both a read standby logical area and a read standby physical area as a read standby area by storage virtualization. And manages a condition under which one or more predetermined requests occur as each trigger, while loading a predetermined data group to be developed in advance in the cache area for each trigger for each of the triggers As data from the data storage area to the storage area The step of copying to a read standby area provided, the step of expanding load data corresponding to each trigger from the read standby area to the cache area at or immediately before the generation of each trigger, and the read As for load data for each trigger to be recorded in the standby logical area, each load data is managed in block units, and data blocks of garbage data determined to be unnecessary for the cache area are extracted and the remaining data blocks are stored. And the step of aligning and recording in the read standby logical area.

A program according to the present invention includes, in response to a predetermined request for reading various data, interface means corresponding to reading of predetermined data recorded, a cache area for storing various data, and various data including the predetermined data. possess a storage area stored in the storage area, the comprises respective both logical area and read standby physical area for reading waiting by the storage virtualization as a reading standby region, the control unit of the storage device, one or a plurality The predetermined data group developed in advance in the cache area for each trigger is managed from the data storage area as each load data for each of the triggers while managing the conditions under which the predetermined requests occur as the respective triggers. the read standby region provided in the storage area A standby area management unit for manufacturing, upon the occurrence of each trigger wherein each or just before, the cache deployment manager to deploy load data corresponding to each trigger from the read waiting area in the cache area, the read The load data is managed in units of blocks for load data for each trigger to be recorded in the standby logical area, and it is operated as a means for deleting data blocks of garbage data determined to be unnecessary for the cache area. It is characterized by

  According to the present invention, it is possible to provide a storage system, a storage device, and a staging method which process data processing storms occurring in the system more efficiently in terms of cost and performance.

FIG. 1 is a block diagram illustrating a storage system of an embodiment. FIG. 2 is a block diagram showing a storage apparatus of an embodiment. FIG. 2 is an explanatory view showing an example of a configuration concept of a storage device according to an embodiment. FIG. 1 is a block diagram showing a storage system of one configuration example. It is an explanatory view showing an example of a cash tag table. It is explanatory drawing which shows the example of the table for cache loads. It is an explanatory view showing an example of a staging trigger table. It is the flowchart which showed the processing operation example of the staging management means. It is the flowchart which showed the processing operation example of the file / block management means. It is the flowchart which showed the processing operation example of the staging volume control means. It is the flowchart which showed the processing operation example of the cache table change means. It is the flowchart which showed the processing operation example of the flowchart which shows the trigger registration means. FIG. 7 is a block diagram showing a storage system of another configuration example. It is an explanatory view showing an example of a cash tag table. It is explanatory drawing which shows the example of the table for cache loads. It is explanatory drawing which shows an example of a user information management table. It is an explanatory view showing an example of a virtual machine management table. It is an explanatory view showing an example of a staging trigger table. It is the flowchart which showed the processing operation example of the login / logout management means. It is the flowchart which showed the processing operation example of the virtual machine information management means.

  Embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are block diagrams showing an example of the configuration of the storage system of the embodiment. FIG. 3 is an explanatory view showing an example of the configuration concept of the storage device of the embodiment.

  The storage system 1 includes a host system 2 and a storage system 3. The host device 2 and the storage device 3 are communicably connected.

  The host device 2 is an information processing device that provides a service built for various applications. The host device 2 may be a plurality of information processing device groups. Further, it sends a request for reading and writing various data to the storage device 3. It also has a management function of the storage device 3.

  The storage apparatus 3 includes an interface unit 10, a cache device 20, a storage device 30, a read standby area management unit 40, and a cache expansion management unit 50. Note that one or both of the read standby area management unit 40 and the cache deployment management unit 50 need not necessarily be provided in the storage apparatus 3. If management of various data stored in the storage device 3, staging management, file system, volume management, etc. is possible, for example, it may be provided on the host side.

  The interface unit 10 is an interface with the host device 2. The interface unit 10 appropriately includes control means responsible for data transmission between the host device 2 and the cache device 20 or the storage device 30 in response to a request from the host device 2 according to the device mode.

  The cache device 20 is a memory device or an SSD operating as a cache area, and is a storage device having higher speed I / O characteristics than the storage device 30. The cache device 20 may adopt a hierarchical structure as needed.

  The storage device 30 is configured of a combination of a large capacity storage medium such as an HDD or a large capacity storage medium as a storage area, and stores a large amount of data. Also, the storage device 30 includes a read standby area.

  The read standby area management unit 40 manages conditions under which one or more predetermined requests occur as triggers of each. In addition, the standby area management unit 40 sets a predetermined data group to be developed in advance in the cache device 20 for each trigger in the read standby area of the storage device 30 as each load data (staging data) for each trigger. Record. In other words, the load data group linked to the trigger is read out and prepared in advance in the waiting area.

  In the read standby area, it is desirable that both the read standby logical area and the read standby physical area be prepared separately from the data storage area that the storage device 3 uses for the host or the like.

  Further, the read standby area management unit 40 manages the contents of load data for each trigger in association with management information (events and history) collected in association with various triggers and manages load data of the read standby area. Reconstructing based on the management information may be sequentially performed.

  Further, in the case of adopting a system configuration that can be managed for each block unit of the logical volume, it is desirable to execute the following processing as reconstruction of load data.

  The read standby area management unit 40 arranges volumes by extracting blocks of garbage data (dirty data) determined to be unnecessary to be expanded in the cache area in the load data of each trigger as rebuilding of load data. cure. This processing improves the throughput at the time of sequential access to the cache or disk when a request corresponding to the trigger is received. In particular, when securing the cache area in the storage area of the SSD, it works beneficially from the read / write characteristics of the data block of the SSD. Note that only deleting garbage data contributes to reduction of the required cache area.

  The cache deployment management unit 50 loads corresponding load data from the read standby logical area to the cache area at or immediately before the occurrence of various triggers. When the cache area adopts a hierarchical structure, cache elements to which individual load data are to be cached may be selected according to the order of priority among the load data to be staged. It is desirable that load data to be staged in the primary cache have higher priority than load data to be staged in the secondary cache.

  For example, if the hit rate in the past is linked in advance to load data and data included in the load data, and high staging priority is given to load data with high hit rate, priority is given to load data useful for the primary cache side. Can be staged.

  The staging priority may be determined artificially, or the value may be calculated and compared using management information and data amount (number of data blocks) collected in association with the trigger. Also, it may be linked to individual data included in the load data. Also, the type of trigger condition may be used as a coefficient.

  Note that it is also useful to set the read standby logical area built in the storage area as inaccessible from the user or the host. For example, inaccessible at the volume level may be realized, or inaccessible at other levels (file, data block, storage device, etc.).

  The storage system 1 of the present embodiment operates as follows. The description of the known processing operation is simplified or omitted.

Preparation process:
The storage system 1 uses the read standby area management unit 40 as a preparation step to manage a condition that causes an expected high load condition or a condition that a group of read requests occur as a trigger group. When each storage system 1 detects a high load state by itself, each trigger may extract the request or condition that is the cause, or may be registered from the host device 2 or the like. For example, when the host device 2 is a server providing a virtual desktop, login requests and logout requests from client terminals can be set as trigger conditions. Moreover, it is also possible to group a plurality of login requests and set the occurrence of a predetermined number of login requests, the time zone, and the like as one trigger condition. By grouping a plurality of requests in this way, it is possible to adjust the data granularity and frequency when performing staging. The service provision environment can be set as the trigger condition. For example, it may be added that the service environment for providing virtual desktops is established in the host, and that the client terminal receiving the provision of virtual desktops is connected to the network.
Further, the read standby area management unit 40 records a predetermined data group developed in the cache device 20 for each trigger in the read standby logical area prepared in the storage device 30 as each load data for each trigger. Do.

Staging process:
The storage system 1 monitors the occurrence of various trigger conditions as a staging process.
In the storage system 1, as a staging process, the cache deployment management unit 50 deploys the corresponding load data from the read standby logical area to the cache area when or immediately before the condition set in the trigger occurs.

Request response process:
After that, the storage system 1 executes data transfer between the host system 2 and the storage device 3 generated due to various requests, data read processing in the storage system 3 and the like in accordance with the requirements. At this time, since the storage system 1 stores the necessary data in the cache area of the storage device 3 in advance, the storage system 1 finishes processing the request efficiently.

  According to this processing algorithm, the hit rate of data expanded in the cache area is increased. As a result, the relationship between performance and cost is improved.

  In addition, if the read standby area management unit 40 executes to sequentially rebuild the contents of the load data for each trigger, a further improvement in the hit rate can be expected.

  Further, if garbage data in the load data is removed for each block unit of the logical volume by the read standby area management unit 40, it is possible to reduce the load data amount for each trigger developed in the cache area. As a result, it is possible to increase the number and amount of load data that can be expanded in the cache area, and to use the cache without wasting it.

  In addition, if the read standby area management unit 40 executes the rearrangement in the volume after removing the garbage data, the possibility of the continuous read at the time of the sequential access to the cache or the disk is improved. As a result, throughput is improved.

  For example, when the host 2 is a thin client server that provides virtual desktops to many users, a time zone can be adopted as a trigger. In this thin client system, login data for one or more users who are expected to log in are constructed in a load file for each time zone (each time) partitioned at an arbitrary interval, and they are stored in a read standby logical area. Store in advance. After that, the storage device 3 appropriately expands the data in the cache area when the time set with the appropriate load file (= appropriate login data) as the trigger condition is reached as time passes. This can mitigate the effects of peaks caused by one or more users logging in.

  That is, by configuring and operating the storage system 1 in this way, storms of data processing that occur in the system can be processed more efficiently in terms of cost and performance. In the above description, the reading function from the storage area and the cache area has been described, but the improvement of the reading ability reduces the waiting time of the operation unit, and increases the time and cache amount for writing. . As a result, the improvement of the reading ability works well for the arithmetic ability and the writing ability.

  Next, two configuration examples of the storage system will be described.

FIG. 4 is a block diagram showing a configuration example of a storage system. 5 to 7 are explanatory diagrams exemplifying each table information.
In this embodiment, a storage system is configured by the storage apparatus 100, the business host group 300, and the management host 400.

  The storage apparatus 100 includes an interface unit, a cache area, a storage area, and a read standby area management unit and a cache expansion management unit. In this configuration example, a staging management unit 200, a file / block management unit 210, a staging volume control unit 230, and a cache table changing unit 240 are provided as read standby area management unit and cache expansion management unit.

  The cache area operates in a hierarchical structure with the cache module 110 and the L2 cache pool 120. In the present configuration, the L2 cache pool 120 using the SSD disk group 130 as the secondary cache is used.

  In the storage area, read standby areas are prepared for each of the physical area and the logical area. The read standby area is the illustrated pre-staging disk pool 160 (physical area) and the pre-staging volume group 150 (logical area). Also, the pre-staging volume group 150 is constructed as a special volume that is not shown to the business host group.

  In the storage area, a plurality of logical disk groups 140 for use by the business host 300 are constructed.

  In this configuration example, the management means implements its function using various tables (cache tag table 260, cache load table 270, staging trigger table 420).

  The cache tag table 260 is table information indicating the arrangement of load data expanded in the cache.

  The cache loading table 270 is table information indicating the arrangement of load data recorded in the logical volume.

  The staging trigger table 420 is table information for managing each trigger.

  The staging management unit 200 periodically compares the current status with the trigger condition recorded in the staging trigger table 420, and requests the cache table changing unit 240 to stage the corresponding load data when the condition is satisfied.

  The file / block management unit 210 monitors an I / O characteristic corresponding to the trigger condition, a notification that the trigger condition is met, and an internal state of the system (for example, a time zone or activation of an arbitrary host). Also, the file / block management unit 210 identifies a data block to be load data recorded in the logical disk group 140 and copies it to the pre-staging volume group 150 when the trigger condition is satisfied. The identification of the data block may be performed by mapping the file and the block. In the pre-staging volume group 150, it is desirable that addresses and block arrangements be recorded side by side in order for each trigger. By recording in order in the pre-staging volume group 150, the information is recorded in order in the continuous recording area of the pre-staging disk pool 160. As a result, when accessing load data for each trigger, recorded data can be read out continuously and efficiently by sequential read. Also, data may be handled in file units instead of block units.

  The staging volume control unit 230 deletes unnecessary data that may become dirty data when the data is updated and staged in a cache within the pre-staging volume group 150. In addition, the staging volume control means 230 carries out pre-filling processing of the deleted area in order to enable sequential access in the pre-staging volume group 150.

  The cache table changing means 240 is created based on the I / O characteristics, and stages load data for each trigger recorded in the pre-staging volume group 150 in the cache and the secondary cache.

  The business host group 300 has an I / O issue function for the logical disk group 140 accessible in the storage area.

  The management host 400 has a trigger registration unit 410 that sets the operation policy set in the staging trigger table 420 by the operation manager 500 in the storage apparatus 100. The registration of the staging trigger table 420 in the storage device 100 may be performed in any manner.

  FIG. 5 is an explanatory view showing the cache tag table 260. As shown in FIG. The cache tag table 260 is a table listing data storage addresses and block layouts. A cache tag table is created for the cache module and the SSD.

  FIG. 6 is an explanatory view showing the cache loading table 270. As shown in FIG. The cache loading table 270 is a table in which the usage block layout on the pre-staging volume group 150, the logical disk number, the usage block layout on the logical disk group 140, and the valid / invalid flag are listed. The cache load table can be mapped at the block level or at the file level.

  FIG. 7 is an explanatory view showing the staging trigger table 420. As shown in FIG. The staging trigger table 420 registers the policy set on the management host 400 in the storage apparatus 100. The staging trigger table 420 is a table that lists staging time, file accumulation start time, and file accumulation time. In this example, the trigger of time is shown, but the trigger may be set by I / O characteristics or event-driven in operation. In addition, triggers including different setting conditions such as a time trigger, an I / O characteristic trigger, and an event driven trigger may be mixed. Also, one trigger may include different condition factors such as time and I / O characteristics.

  8 to 12 are flowcharts showing processing operations of the staging management unit 200, the file / block management unit 210, the staging volume control unit 230, and the cache table changing unit 240.

FIG. 8 is a flowchart showing the operation of the staging management unit 200.
The staging management means 200 is a means that operates periodically during operation. The staging management unit 200 that has started the operation sequentially refers to the staging trigger table 420 (S101).

  Next, the staging management means 200 confirms whether the trigger condition is satisfied (S102). If the condition is satisfied, the staging management unit 200 requests the cache table changing unit 240 to stage the load data (S103). On the other hand, if the condition is not met, the staging management means 200 returns to the beginning.

FIG. 9 is a flowchart showing the operation of the file / block management unit 210.
The file / block management unit 210 starts the operation when a condition (I / O or the like) corresponding to the trigger is detected (S201).

  The file / block management means 210 maps the blocks of the logical disk group 140 and the required file (S202).

  Next, the file / block management unit 210 copies the corresponding block group identified by the mapping from the logical disk group 140 to the pre-staging volume group 150 (S203).

  When copying the corresponding block group, the file / block management unit 210 checks whether or not the data corresponding to the present data already exists in the pre-staging volume group 150 (S204).

  If there is no data, the file / block management unit 210 updates the cache loading table 270 as valid data (S205).

  On the other hand, if the data exists, the file / block management unit 210 flags the old data in the cache loading table 270 as invalid data (S206). This is because it can be determined that the corresponding data has been updated, and therefore, it is not used as staging data.

FIG. 10 is a flowchart showing the operation of the staging volume control unit 230.
The staging volume control means 230 operates periodically during operation of the system.

  The staging volume control unit 230 refers to the cache loading table 270 (S301).

  Next, the staging volume control means 230 confirms the presence or absence of data for which the valid / invalid flag is invalid (S302). If there is no data set to be invalid, the staging volume control means 230 completes the process without doing anything.

  If there is data set to be invalid, the staging volume control unit 230 deletes the corresponding data from the pre-staging volume group 150 and also pre-fills the deleted data portion (S303). This ensures sequential data placement.

  Thereafter, the staging volume control means 230 updates the cache loading table 270 and completes the processing (S304).

FIG. 11 is a flowchart showing the operation of the cache table changing means 240.
The cache table change unit 240 receives the staging request from the staging management unit 200 and starts the operation.

  The cache table changing means 240 refers to the cache load table 270 and specifies load data to be staged (S401).

  The cache table changing means 240 stages the load data to be staged in the cache area (the cache module 110 and the L2 cache pool 120) (S402).

  The cache table changing unit 240 that has completed the staging updates the cache tag table 260 (S403).

FIG. 12 is a flowchart showing the operation of the trigger registration unit 410.
The trigger registration unit 410 operates at the timing when the operation manager 500 registers / updates the staging trigger table 420.

  The trigger registration means 410 registers / updates the inputted policy (trigger condition etc.) in the staging trigger table 420 (S501).

  Thereafter, the trigger registration unit 410 sends a new staging trigger table 420 to the storage device 100, and registers / updates the trigger policy (S502).

As described above, by operating the storage system management means, it is possible to reduce the amount of expensive SSDs and memory secured at the time of sizing to avoid a temporary high load.
The reason is that staging is appropriately performed each time according to the trigger. This makes the staged data more appropriate and results in an improved hit rate compared to staging without triggers. When securing equivalent performance, the amount of expensive SSDs and memory can be reduced.

  In addition, even if a large amount of data to be staged does not fit in the cache memory, the speed of reading the corresponding data from the storage area is faster than that of the existing method.

  From another point of view, at the same cost, the method has improved performance as compared to the method of staging without using a trigger.

  Also, it becomes possible to prepare data in which sequential access is secured in the storage area and cache area according to a trigger such as an I / O characteristic. This can improve the performance at low cost.

  In addition, when a hierarchical structure is adopted for the cache area, data which can not be spared in the primary cache can be staged in the secondary cache (SSD). Furthermore, even in the case where even secondary caches can not be obtained and the login data can be read from the disk device, the data can be read sequentially from the pre-staging volume group, so that the influence of concentration of login processing can be reduced.

  Next, another configuration example will be described. The same parts as those in the above configuration example simplify the description. This configuration example reduces the impact of a login storm. In many login storms, when a large number of users log in at the same time, there are factors such as a large number of writes by copying a profile and a large number of reads by a virus scan after login. In this embodiment, these concentrated data processing loads are efficiently processed.

FIG. 13 is a block diagram showing an example of the configuration of another storage system.
14 to 18 are explanatory diagrams exemplifying each table information.
The present embodiment has a means for notifying an event in the business host group 300.

The storage apparatus 100 has an interface unit, a cache area, a storage area, and a standby area management unit and a cache expansion management unit. In this configuration example, in addition to the staging management unit 200, the file / block management unit 210, the staging volume control unit 230, and the cache table changing unit 240, the login / logout management unit 250 is used as a standby area management unit and cache expansion management unit. Have.
The cache area and the storage area are the same as in the previous configuration example.

In this configuration example, the management means uses the user information management table 280 in addition to the cache tag table 260, the cache loading table 270, and the staging trigger table 420.
The cache tag table 260 is table information indicating the arrangement of load data expanded in the cache.
The cache loading table 270 is table information indicating the arrangement of load data recorded in the logical volume. In this configuration example, it is a table that manages data blocks of login data for each user.
The user information management table 280 is table information for managing the storage area used by each user (virtual machine). In this configuration example, management information is recorded for each user.
The staging trigger table 420 is table information for managing each trigger.

  The staging management unit 200, the file / block management unit 210, the staging volume control unit 230, and the cache table changing unit 240 are the same as the above configuration example.

  In this configuration, in the staging volume control unit 230, data blocks constituting each user login information included in the load data in the pre-staging volume group 150 prepared for each time are used as the login history and the attribute of the corresponding user. Organize sequentially based on. For example, referring to the user information management table, when the number of logins of the corresponding user falls below the threshold, when the user ID is deleted, when the staging unnecessary flag is set, etc. Implement block deletion and justification.

  The cache table changing means 240 stages load data in the cache area immediately before the time when each user will log in.

  The login / logout managing means 250 records the time when the user logged in at the time of login completion in the user information management table 280. At this time, based on the past login time accumulated in the user information management table 280 and the current login time, the time immediately before the login time zone is set as the next staging time.

  In this setting, according to various policies set in the staging trigger table 420, one or more login time candidates are derived so as to be in time for the user to login and not to cache for a long time more than necessary. For example, a certain user is extracted as a certain time zone of morning and a certain time zone of daytime as the number of logins being equal to or more than a threshold.

  Further, the login / logout managing unit 250 requests the file / block managing unit 210 to update the pre-staging volume group 150 from the information described in the virtual machine management table 320 at the time of logout.

  The business host group 300 provides each user with a virtual machine group. Each virtual machine has an area (area of the logical disk group 140) accessible to the storage area. Further, the business host group 300 has a virtual machine information management unit 310 and a virtual machine management table 320. The virtual machine information management means 310 notifies the login / logout management means 250 of the user ID and login time when login of each virtual machine is completed, and the information of the virtual machine management table 320 when logging out. Each virtual machine may directly notify the login / logout managing means 250 of various information.

  The management host 400 has a trigger registration unit 410 that sets the operation policy set in the staging trigger table 420 by the operation manager 500 in the storage apparatus 100. The registration of the staging trigger table 420 in the storage device 100 may be performed in any manner.

  14 and 15 are explanatory diagrams showing the cache tag table 260 and the cache loading table 270.

  FIG. 16 is an explanatory view showing the user information management table 280. As shown in FIG. In the present configuration example, the user information management table 280 is a table that the storage apparatus 100 holds and lists user IDs, login status, staging time, staging volume usage block arrangement, and past login time information.

  FIG. 17 is an explanatory view showing the virtual machine management table 320. As shown in FIG. In the present configuration example, the virtual machine management table 320 is a table in which virtual machine arrangement addresses are listed for each user ID (virtual machine).

  FIG. 18 is an explanatory view showing the staging trigger table 420. As shown in FIG. In the present configuration example, the staging trigger table 420 is a table listing the staging time, the interval for staging, the number of times of login time accumulation in the past, and the threshold number of times of login.

  The processing operations of the staging management unit 200, the file / block management unit 210, the staging volume control unit 230, and the cache table changing unit 240 are substantially the same as the flowchart shown above. In the present embodiment, the user information management table 280 is referred to in the middle of each process. The operations of the login / logout management means 250 and the virtual machine information management means 310 will be described below.

  FIG. 19 is a flowchart showing an operation example of the login / logout managing means 250. The login / logout management unit 250 operates when the virtual machine information management unit 310 operating on the business host group 300 notifies the event of login / logout to the virtual machine.

  First, the login / logout managing means 250 determines whether the notification is login or logout (S601).

  If the notification is a login, the login / logout managing means 250 adds the corresponding login time to the user ID of the user information management table 280 (S602).

  After that, the login / logout management unit 250 sets the next staging time of the logged-in user with reference to the staging trigger table 420 and the user information management table 280 (S603).

  Next, the login / logout managing means 250 changes the status of the user information management table 280 to login and completes the process (S604).

  On the other hand, if the notification is a logout, the login / logout management means 250 updates the status of the user information management table 280 to logout (S605).

  Thereafter, the login / logout management means 250 notifies the file / block management means 210 of a request for copying data necessary for login to the pre-staging volume group 150 (S606).

  FIG. 20 is a flowchart showing an operation example of the virtual machine information management unit 310. The virtual machine information management unit 310 starts the operation at the timing when the user logs in or out of the virtual machine.

  The virtual machine information management unit 310 determines the login or logout of an arbitrary user as an event (S701).

  When the user logs in, the login / logout unit 250 operating on the storage apparatus 100 is notified of the user ID of the user and the login time (S702).

  On the other hand, when the user logs out, the virtual machine information management means 310 refers to the virtual machine management table 320 to identify the arrangement of virtual machines (S104).

  Thereafter, the virtual machine information management unit 310 notifies the login / logout unit 250 of the user ID and the arrangement of the virtual machine (S703).

  The flow of operation for providing a virtual desktop environment to many users using the above configuration example will be briefly described in each phase.

Before operation:
The operation manager 500 creates an environment that enables the business host group 300 to provide virtual machines to users.
The operation manager 500 manually or automatically creates the pre-staging disk pool 160 and the pre-staging volume group 150 based on the operation policy.
Before the operation manager 500 starts the operation, various policies are set in the staging trigger table 420 on the management host 400, and the staging device table 420 is notified to the storage apparatus 100.

Regular staging process:
The storage apparatus 100 refers to the time information and staging trigger table 420 and the user information management table 280, and stages login information in the cache area at timing when each user logs in.
In this staging process, the data recorded in the pre-staging volume 150 is optimized in consideration of sequential access, so staging can be performed at high speed.

The storage apparatus 100 refers to the cache loading table 270 and the user information management table 280, and organizes unnecessary data in the load data in the pre-staging volume prepared for each time. This arrangement speeds up staging and speeds up access to data on the drive in the event of a cache miss.

As described above, by operating the storage system management means, it is possible to reduce the amount of expensive SSDs and memory secured at the time of sizing to avoid a temporary high load.
The reason is that staging is appropriately performed each time according to the trigger. This makes the staged data more appropriate and results in an improved hit rate compared to staging without triggers. When securing equivalent performance, the amount of expensive SSDs and memory can be reduced.

  In addition, even if a large amount of data to be staged does not fit in the cache memory, the speed of reading the corresponding data from the storage area is faster than that of the existing method.

  From another point of view, at the same cost, the method has improved performance as compared to the method of staging without using a trigger.

  Also, it becomes possible to prepare data in which sequential access is secured in the storage area and cache area according to a trigger such as an I / O characteristic. This can improve the performance at low cost.

  In addition, when a hierarchical structure is adopted for the cache area, data which can not be spared in the primary cache can be staged in the secondary cache (SSD). Furthermore, even in the case where even secondary caches can not be obtained and the login data can be read from the disk device, the data can be read sequentially from the pre-staging volume group, so that the influence of concentration of login processing can be reduced.

  The storage system management means may be realized using a combination of hardware and software. In a mode in which hardware and software are combined, a management program may be expanded in the RAM, and hardware such as a control unit (CPU) may be operated as management means based on the program. Also, this program may be recorded non-temporarily on a recording medium and distributed. The program recorded on the recording medium is read into the memory via a wired, wireless, or recording medium itself to operate the control unit and the like. Incidentally, examples of the recording medium include an optical disk, a magnetic disk, a semiconductor memory device, a hard disk and the like.

  Although the embodiment has been illustrated and described above, modifications such as separation and merging of block configurations and replacement of procedures are free as long as the spirit and functions of the present invention are satisfied, and the above description limits the present invention. It is not a thing.

  As described above, according to the present invention, it is possible to provide a storage system, a storage device, and a staging method that process storms of data processing occurring in the system more efficiently in terms of cost and performance.

Also, some or all of the above embodiments may be described as follows. The following appendices do not limit the present invention at all.
[Supplementary Note 1]
A host that sends out a predetermined request to read various data;
Interface means corresponding to reading of predetermined data recorded in response to the predetermined request for reading various data from the host;
Cache area for storing various data,
A storage area storing various data including the predetermined data;
Storage with
A predetermined data group pre-expanded in the cache area for each trigger is managed as load data for each trigger while managing the conditions under which one or more predetermined requests occur as each trigger. Means of recording,
Means for expanding corresponding load data from the standby area to the cache area when and / or immediately before various triggers occur;
Storage system characterized in that.

[Supplementary Note 2]
The storage system according to the above-mentioned addition, further comprising means for reconstructing the load data of the read standby area based on the management information acquired by associating the content of the load data for each trigger with the trigger.

[Supplementary Note 3]
The storage system according to the above-mentioned addition, wherein the read standby area is provided with both a read standby logical area and a read standby physical area.

[Supplementary Note 4]
The load data for each trigger to be recorded in the read standby logical area is further managed by a block unit of the logical volume, and further includes means for deleting a block of garbage data determined to be unnecessary for the cache area. A storage system as described in the above-mentioned appendix, characterized in that:

[Supplementary Note 5]
The load data for each trigger to be recorded in the read standby logical area is managed in block units of the logical volume, and blocks of garbage data determined to be unnecessary to be expanded in the cache area are extracted to be data in the volume A storage system according to any of the preceding claims further comprising means for aligning the blocks.

[Supplementary Note 6]
The storage system according to the above-mentioned addition, wherein the area for reading standby of the storage area is set inaccessible from the user terminal and the host.

[Supplementary Note 7]
The cache area has a hierarchical structure using different cache elements,
Load elements to be cached according to the priority among load data to be simultaneously present in the cache area based on the load data to be staged and / or the staging priority given to the data included in the corresponding load data A storage system according to the above-mentioned appendix, further comprising means for selecting.

[Supplementary Note 8]
Interface means corresponding to reading of predetermined data recorded in response to a predetermined request for reading various data;
Cache area for storing various data,
A storage area storing various data including the predetermined data;
A predetermined data group pre-expanded in the cache area for each trigger is managed as load data for each trigger while managing the conditions under which one or more predetermined requests occur as each trigger. Means of recording,
Means for expanding corresponding load data from the standby area to the cache area when and / or immediately before various triggers occur;
A storage apparatus characterized by having:

[Supplementary Note 9]
The storage apparatus according to the above-mentioned addition, further comprising means for re-building the load data of the read standby area based on the management information collected by associating the content of the load data for each trigger with the trigger.

[Supplementary Note 10]
The storage device according to the above-mentioned addition, wherein the read standby area is provided with both a read standby logical area and a read standby physical area.

[Supplementary Note 11]
The load data for each trigger to be recorded in the read standby logical area is further managed by a block unit of the logical volume, and further includes means for deleting a block of garbage data determined to be unnecessary for the cache area. The storage apparatus as set forth in the above-mentioned appendix, characterized in that:

[Supplementary Note 12]
The load data for each trigger to be recorded in the read standby logical area is managed in block units of the logical volume, and blocks of garbage data determined to be unnecessary to be expanded in the cache area are extracted to be data in the volume A storage apparatus according to any of the preceding claims, further comprising means for aligning the blocks.

[Supplementary Note 13]
The storage apparatus as set forth in the above-mentioned, wherein the read standby area of the storage area is set to be inaccessible from the user terminal and the host.

[Supplementary Note 14]
The cache area has a hierarchical structure using different cache elements,
Load elements to be cached according to the priority among load data to be simultaneously present in the cache area based on the load data to be staged and / or the staging priority given to the data included in the corresponding load data The storage apparatus according to the above-mentioned additional statement, further comprising means for selecting.

[Supplementary Note 15]
In response to a predetermined request for reading various data, it has interface means corresponding to reading of predetermined data recorded, a cache area for storing various data, and a storage area for storing various data including the predetermined data. Storage device,
A predetermined data group pre-expanded in the cache area for each trigger is managed as load data for each trigger while managing the conditions under which one or more predetermined requests occur as each trigger. A first step of recording;
A second step of expanding corresponding load data from the standby area to the cache area when and / or immediately before the occurrence of various triggers;
A method of staging in a storage device, comprising:

[Supplementary Note 16]
The staging method as set forth above, further comprising the step of reconstructing the load data of the read standby area based on the management information collected by associating the content of the load data for each trigger with the trigger.

[Supplementary Note 17]
The staging method according to the supplementary note, wherein the read standby area is provided with both a read standby logical area and a read standby physical area.

[Supplementary Note 18]
A process of managing load data for each trigger recorded in the read standby logical area in block units of logical volumes and deleting blocks of garbage data determined to be unnecessary to expand in the cache area is further included. The staging method as described in the above-mentioned attached matter characterized by the above.

[Supplementary Note 19]
The load data for each trigger to be recorded in the read standby logical area is managed in block units of the logical volume, and blocks of garbage data determined to be unnecessary to be expanded in the cache area are extracted to be data in the volume 7. A staging method according to claim 1 further comprising the step of aligning the blocks.

[Supplementary Note 20]
The staging method according to the supplementary note, wherein the read standby area of the storage area is set inaccessible from the user terminal and the host.

[Supplementary Note 21]
The cache area has a hierarchical structure using different cache elements,
Load elements to be cached according to the priority among load data to be simultaneously present in the cache area based on the load data to be staged and / or the staging priority given to the data included in the corresponding load data 7. A staging method as recited in the above-mentioned appendix, further comprising the step of selecting.

[Supplementary Note 22]
In response to a predetermined request for reading various data, it has interface means corresponding to reading of predetermined data recorded, a cache area for storing various data, and a storage area for storing various data including the predetermined data. The control unit of the storage device
A predetermined data group pre-expanded in the cache area for each trigger is managed as load data for each trigger while managing the conditions under which one or more predetermined requests occur as each trigger. A standby area management unit for recording;
A cache expansion management unit for expanding corresponding load data from the standby area to the cache area when and / or immediately before various triggers occur;
A program characterized by operating as.

[Supplementary Note 23]
The control unit is operated as means for reconstructing the load data of the read standby area based on the management information collected by associating the content of the load data for each trigger with the trigger. Programs.

[Supplementary Note 24]
The program according to the supplementary note, wherein the control unit is operated to use both the read standby logical area and the read standby physical area as the read standby area.

[Supplementary Note 25]
The control unit manages load data for each trigger for recording in the read standby logical area on a block-by-block basis of a logical volume, and deletes blocks of garbage data for which expansion to the cache area is determined to be unnecessary. The program according to the above-mentioned addition, characterized in that it operates as means for

[Supplementary Note 26]
The control unit manages load data for each trigger for recording in the read standby logical area on a block-by-block basis of a logical volume, and removes blocks of garbage data determined to be unnecessary for the cache area. The program according to the above-mentioned addition, characterized in that it operates as means for aligning data blocks within a volume.

[Supplementary Note 27]
The program according to the above-mentioned addition, characterized in that the control unit is operated to set the read standby area of the storage area as inaccessible from the user terminal and the host.

[Supplementary Note 28]
The storage device has a hierarchical structure using different cache elements as a cache area,
Priority among load data to be simultaneously made in the cache area based on a staging priority given to load data to be staged and / or data included in the load data to be executed, the control unit of the storage apparatus The program according to the above-mentioned addition, characterized in that it operates as means for selecting a cache element to be a cache destination according to the above.

  The present invention can be applied to a storage system having a processing peak including a reading process in which occurrence can be predicted in advance in an information processing system. For example, it can be employed in a data center that provides a cloud environment or an in-house storage server.

1 storage system 2 host device 3 storage device 10 interface unit (interface means)
20 cache device 30 storage device 40 area management unit for reading standby (area management unit for reading standby)
50 Cache Deployment Management Department (Cache Deployment Management Means)
100 storage device 110 cache module 120 L2 cache pool 130 SSD disk group 140 logical disk group 150 pre-staging volume group 160 pre-staging disk pool 200 staging management means 210 file / block management means 230 staging volume control means 240 cache table changing means 250 login / logout management means 260 cache tag table 270 cache loading table 280 user information management table 300 business host group 310 virtual machine information management means 400 management host 410 trigger registration means 420 staging trigger table

Claims (10)

A host that sends out a predetermined request to read various data;
Interface means corresponding to reading of predetermined data recorded in response to the predetermined request for reading various data from the host;
Cache area for storing various data,
A storage area storing various data including the predetermined data in a data storage area;
Storage with
While managing 1 to a condition in which a plurality of predetermined request is generated as each of the trigger, the data predetermined data group pre-expanded in the cache area for each trigger, as each of the load data for each of the respective trigger A unit for copying from a storage area to a read standby area provided in the storage area ;
It means for deploying immediately before or during triggering of each occurrence of the respective, in the cache area to load data corresponding to each trigger from the read standby region,
Only including,
The read standby area is provided with both a read standby logical area and a read standby physical area by storage virtualization.
A means for managing load data for each block in units of blocks for load data for each trigger to be recorded in the read standby logical area, and deleting data blocks of garbage data determined to be unnecessary to be expanded in the cache area A storage system, further comprising: A host that sends out a predetermined request to read various data;
Interface means corresponding to reading of predetermined data recorded in response to the predetermined request for reading various data from the host;
Cache area for storing various data,
A storage area storing various data including the predetermined data in a data storage area;
Storage with
A predetermined data group developed in advance in the cache area for each trigger while managing conditions under which one or more predetermined requests occur as each trigger, the data as load data for each of the triggers A unit for copying from a storage area to a read standby area provided in the storage area;
And means for expanding load data corresponding to each trigger from the read standby area to the cache area at or immediately before the generation of each of the triggers.
Including
The read standby area is provided with both a read standby logical area and a read standby physical area by storage virtualization.
With respect to load data for each trigger to be recorded in the read standby logical area, each load data is managed in block units, and data blocks of garbage data determined to be unnecessary to be expanded in the cache area are extracted and the remaining And a means for aligning and recording data blocks in the read wait logic area.
Storage system characterized by Based on management information collected in association with the trigger, wherein the load data for each trigger that is recorded in the read waiting area, to claim 1 or 2, further comprising a means to rebuild sequentially Storage system. The predetermined request is a login request of each user,
Each of the triggers is associated with a condition under which each user's login request may occur.
The storage system according to any one of claims 1 to 3, characterized in that: The storage system according to any one of claims 1 to 4 , wherein the read standby area of the storage area is set to be inaccessible from the user terminal and the host. The cache area has a hierarchical structure using different cache elements,
Load elements to be cached according to the priority among load data to be simultaneously present in the cache area based on the load data to be staged and / or the staging priority given to the data included in the corresponding load data Furthermore, look at including the means for selecting,
The storage system according to any one of claims 1 to 5 , wherein the staging priority value is calculated using management information or data amount collected in association with a trigger . Interface means corresponding to reading of predetermined data recorded in response to a predetermined request for reading various data;
Cache area for storing various data,
A storage area storing various data including the predetermined data in a data storage area;
While managing 1 to a condition in which a plurality of predetermined request is generated as each of the trigger, the data predetermined data group pre-expanded in the cache area for each trigger, as each of the load data for each of the respective trigger A unit for copying from a storage area to a read standby area provided in the storage area ;
It means for deploying immediately before or during triggering of each occurrence of the respective, in the cache area to load data corresponding to each trigger from the read standby region,
I have a,
The read standby area is provided with both a read standby logical area and a read standby physical area by storage virtualization.
A means for managing load data for each block in units of blocks for load data for each trigger to be recorded in the read standby logical area, and deleting data blocks of garbage data determined to be unnecessary to be expanded in the cache area A storage apparatus, further comprising: In response to a predetermined request for reading various data, an interface unit corresponding to reading of predetermined data recorded, a cache area for storing various data, and a storage area storing various data including the predetermined data in the data storage area When, the storage devices having,
As a read standby area, both of the read standby logical area and the read standby physical area are provided by storage virtualization.
While managing 1 to a condition in which a plurality of predetermined request is generated as each of the trigger, the data predetermined data group pre-expanded in the cache area for each trigger, as each of the load data for each of the respective trigger Copying from a storage area to a read standby area provided in the storage area ;
A step of the last expansion also trigger when each occurrence of the each of the cache area to load data corresponding to each trigger from the read standby region,
Managing load data in units of blocks for load data for each trigger to be recorded in the read standby logical area, and deleting data blocks of garbage data determined to be unnecessary to be expanded in the cache area; ,
A method of staging in a storage device, which is executed by including it in the staging process. In response to a predetermined request for reading various data, an interface unit corresponding to reading of predetermined data recorded, a cache area for storing various data, and a storage area storing various data including the predetermined data in the data storage area And a storage device having
As a read standby area, both of the read standby logical area and the read standby physical area are provided by storage virtualization.
A predetermined data group developed in advance in the cache area for each trigger while managing conditions under which one or more predetermined requests occur as each trigger, the data as load data for each of the triggers Copying from a storage area to a read standby area provided in the storage area;
Expanding load data corresponding to each trigger from the read standby area to the cache area at or immediately before the occurrence of each of the triggers;
With respect to load data for each trigger to be recorded in the read standby logical area, each load data is managed in block units, and data blocks of garbage data determined to be unnecessary to be expanded in the cache area are extracted and the remaining Aligning and recording data blocks in the read standby logic area;
A method of staging in a storage device, which is executed by including it in the staging process. In response to a predetermined request for reading various data, an interface unit corresponding to reading of predetermined data recorded, a cache area for storing various data, and a storage area storing various data including the predetermined data in the data storage area If, have a, the control unit of the storage device having both a logical area and a reading standby physical area for reading stand respectively by the storage virtualization as a reading standby region,
While managing 1 to a condition in which a plurality of predetermined request is generated as each of the trigger, the data predetermined data group pre-expanded in the cache area for each trigger, as each of the load data for each of the respective trigger A standby area management unit for copying from a storage area to a read standby area provided in the storage area ;
Just before the trigger each also upon the occurrence of said each cache deployment manager to deploy load data corresponding to each trigger from the read waiting area in the cache region,
Means of managing each load data for each block as load data for each trigger to be recorded in the read standby logical area, and deleting data blocks of garbage data determined to be unnecessary to be expanded in the cache area;
A program characterized by operating as.

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