JP3570798B2 - Continuous data server device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a continuous data server device for storing and delivering a data file composed of a series of continuous data such as a video file in a data file server such as a video server.
[0002]
[Prior art]
A continuous data server computer that handles continuous data such as video and audio has a function of reading continuous data stored in a storage device and continuously delivering or sending the data to a terminal device in real time while synchronizing with time. Such a continuous data server computer stores video data of a plurality of movies and the like, and provides video-on-demand for sending an arbitrary movie in response to a request from a terminal, and provides product information by video via a network. Used in areas such as online shopping. Such a continuous data server computer is required to be capable of sending different continuous data to a large number of users at the same time.
[0003]
A conventional continuous data server computer has a configuration as shown in FIG. That is, the access request to the continuous data issued by the user or the application program is transmitted to the central control device 10 by means such as inter-process communication or communication via a network. The central controller 10 informs each data storage controller 11 of the reading of the requested continuous data. The data storage control device 11 reads the designated continuous data from the data storage device 12 and writes the read continuous data to the main storage device 13. Thereafter, the central control device 10 instructs the communication control device 14 to send out the data on the main storage device 13. If the specified continuous data does not exist in the data storage device 12, the continuous data is read from the archive device 15.
[0004]
A disk device is often used as a data storage device for storing continuous data in a continuous data server computer. Although a magnetic disk device is often used as a disk device, an optical disk, a magneto-optical disk device, or the like may be used in some cases. A semiconductor storage device such as a RAM or an EEPROM may be used instead of the disk device.
[0005]
When a disk is used as a data storage device, if a large number of users simultaneously access different parts of continuous data stored in a specific disk device, the access speed of the disk becomes a bottleneck, and all users can access data in real time. Can not be sent out. This corresponds to a case where a video is stored on one magnetic disk as continuous data, and a case where a large number of users watch one video shifted every one minute.
[0006]
For example, in the case of video data, it is assumed that continuous data is sent to one user terminal at an average speed of 1.5 Mbit / sec. Assuming that the magnetic disk device that stores the video data can read the data at a maximum speed of 2 MByte / sec, one magnetic disk device can only send data to a maximum of 10 users.
[0007]
A technique called striping is used as a method for solving such a bottleneck of the disk device. The striping technique uses a plurality of disk devices to increase the overall data transfer capability (total bandwidth). Further, by dividing one continuous data and storing it on a plurality of disk devices, it is possible for many users to simultaneously access the same continuous data.
[0008]
When striping is performed on n disk devices, the exclusive OR of the data stored on the n disks is obtained, and the value is stored as parity in the (n + 1) th disk, thereby obtaining n + 1 disk devices. Even if one of the disks fails, it can be recovered by calculating the exclusive OR of the data of the other disk devices. This technique is widely known as RAID.
[0009]
By performing striping, it is possible to configure a storage device having a wide bandwidth that can cope with a worst case in which a plurality of users access different portions of the same continuous data. However, even if a plurality of disk devices are connected to one computer as shown in FIG. 2 and the bandwidth is obtained by striping, the number of users who can access simultaneously is limited by the transfer speed of the bus of the computer.
[0010]
It is widely known that the continuous data server device can configure a system with a good cost performance ratio by recording the data in different storage devices according to the frequency of use of the continuous data.
[0011]
That is, data that is frequently used is recorded in a data storage device such as a magnetic disk device having a high recording cost per capacity but a high access speed. Here, the access speed is a time required for cueing from receiving a data request to starting sending the data. Since these devices are connected online, the cueing time can be reduced.
[0012]
For extremely frequently used data, a data storage device such as a semiconductor memory, which has a higher recording cost but a very high access speed, may be used.
On the other hand, data that is used less frequently is recorded and managed in the archive device. An archive device is a storage device such as a magnetic tape, an optical disk, or a magneto-optical disk that has a low recording cost per capacity but a low access speed. These storage devices usually have a removable tape or disk for recording data.
[0013]
That is, the recording medium has a structure that can be removed from a drive device that reads and writes data. As a result, the recording cost per capacity is the price of only the storage medium, which is lower than a non-removable magnetic disk device or the like. However, when a request for data is received, the data cannot be read out unless the recording medium on which the data is recorded is mounted on the drive device, so that the access speed is reduced.
[0014]
The continuous data server device records continuous data having a high access frequency in a data storage device such as a plurality of magnetic disk devices. Video data with a low access frequency is recorded in an archive device using an optical disk or the like. When a request for continuous data not recorded in the magnetic disk device comes, the continuous data is read from the archive device to the data storage device.
[0015]
The continuous data read from the archive device to the data storage device can be sent to the user while reading the data continuously, or sent to the user after reading the data. In the method of sending while reading, the time from when a request from the user comes to when continuous data is sent out is short, but trick play such as fast forward is limited. In the method of sending data after reading, the time from when a request from the user comes to the time when continuous data is sent out becomes longer, but since the data is sent out completely after entering the data storage device, there is no restriction on trick play and the like.
[0016]
[Problems to be solved by the invention]
Conventionally, when continuous data is transferred between an archive device and a data storage device, the continuous data is temporarily written to the main storage device, so that the area of the main storage device that can be used for delivery of the original continuous data is reduced. There was a problem.
[0017]
When transferring continuous data between the archive device and the data storage device, a bus is used when transferring the continuous data between the archive device and the main storage device and between the main storage device and the data storage device. Therefore, there is a problem that the occupation time of the bus that can be used for the delivery of the original continuous data is reduced.
[0018]
As a result, while continuous data is being transferred between the archive device and the data storage device, the number of continuous data (the number of streams) that can be distributed is reduced.
[0019]
Furthermore, for the same reason, when writing continuous data read from the archive device to a specific data storage device, there is a problem that the number of continuous data that can be read from another data storage device and distributed is limited.
[0020]
In particular, in a continuous data server device using a RAID-structured data storage device, while repairing a failed data storage device and continuing to read and write data to be stored in the data storage device from an archive device, one RAID device is used. In the case of performing distribution while restoring continuous data stored in the failed data storage device using the parity of the above, there is a problem that the number of streams that can be distributed decreases before and after the failure occurs.
[0021]
[Means for Solving the Problems]
A continuous data server device according to the present invention (claim 1) includes a first bus, a main storage device connected to the first bus, and a continuous storage device connected to the first bus and connected to an external communication path. A communication control device for outputting data, an archive device capable of storing continuous data and reading desired continuous data, and a second independent of the first bus for transferring continuous data read from the archive device Bus, a plurality of buffer storage devices for temporarily holding continuous data from the second bus, a plurality of data storage devices for storing continuous data, one of the first bus and the data storage device. Connected to one of the buffer storage devices, and reads continuous data from the connected data storage device to the main storage device or the communication control device via the first bus. A plurality of data storage control devices each having a unit for directly transmitting without passing through the buffer storage device, and a unit for reading continuous data temporarily stored from the connected buffer storage device and writing the data to the data storage device; It is characterized by having.
[0022]
A continuous data server device according to the present invention (claim 2) comprises a first bus, a main storage device connected to the first bus, and a continuous storage device connected to the first bus and connected to an external communication path. A communication control device for outputting data, an archive device capable of storing continuous data, a second bus independent of the first bus for transferring continuous data to be written to the archive device, and the second bus A plurality of buffer storage devices for temporarily storing continuous data to be written to the archive device, a plurality of data storage devices for storing continuous data, the first bus, one of the data storage devices, and the buffer It is connected to one of the storage devices, reads continuous data from the connected data storage device, and to the main storage device or the communication control device via the first bus, A plurality of data units each having a unit for directly transmitting data without passing through the buffer storage device, and a unit for reading continuous data from the connected data storage device and writing continuous data for temporary holding in the buffer storage device And a storage control device .
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
In the continuous data server device and the continuous data transfer method of the present invention, one or more dedicated buffer storage devices are provided for each combination of a plurality of data storage control devices and an archive device. That is, when continuous data is transferred from an archive device to a corresponding data storage device via a certain data storage control device, or when continuous data is transferred from a certain data storage device to the archive device via a corresponding data storage control device. In this case, a dedicated buffer storage device between the data storage control device and the archive device is used.
[0026]
With this configuration, during continuous data transfer between the archive device and the data storage control device, the main storage device, the buffer storage device, and the bus used by other data storage control devices are not used. On the other hand, there is no influence such as a decrease in the number of continuous data (the number of streams) that can be distributed simultaneously. That is, continuous data transfer between the archive device and the data storage device, which minimizes the influence on the distribution process, becomes possible.
[0027]
In the continuous data server device of the present invention, a disk device can be used as a data storage device for storing continuous data. Although a magnetic disk device is often used as a disk device, an optical disk, a magneto-optical disk device, or the like may be used in some cases. In addition to the disk device, a semiconductor storage device such as a RAM or an EEPROM can be used.
[0028]
Specifically, a SCSI controller can be used as the data storage control device. One SCSI controller can be connected to a plurality of disk devices having SCSI interfaces. In addition, various interface devices for connecting a disk device, such as a FIBER CHANNEL, can be used.
[0029]
Specifically, a storage device such as a magnetic tape, an optical disk, or a magneto-optical disk, which has a low recording cost per capacity but a low access speed, can be used as the archive device. These storage devices usually have a removable tape or disk for recording data. That is, the recording medium has a structure that can be removed from a drive device that performs only reading / writing or reading of data. As a result, the recording cost per capacity is the price of only the storage medium, which is lower than a non-removable magnetic disk device or the like. However, when a request for data is received, the data cannot be read out unless the recording medium on which the data is recorded is mounted on the drive device, so that the access speed is reduced.
[0030]
Specifically, a semiconductor memory can be used as the buffer storage device. In addition, in parallel with the continuous data transfer between the archive device and the data storage controller, the corresponding continuous data is stored in the data storage device by the data storage controller in accordance with the access request to the continuous data issued by the user or the application program. And stored in the main storage device, and then sent out to the communication path by the communication control device. The path connecting the archive device and the buffer storage device, the data storage control device and the main storage device It is preferable that the path connecting the communication control device and the communication control device be provided independently of each other. Further, it is preferable that the paths connecting the respective data storage control devices and the corresponding buffer storage devices are provided independently of each other. In this case, one buffer storage device is functionally constituted by a memory having two ports so as to be connected to both the path to the corresponding data storage control device and the path to the archive device. good.
[0031]
(Specific example 1)
An example of a specific embodiment of the present invention will be described using the configuration diagram shown in FIG. 1 and the operation procedure of the central control device shown in FIG.
[0032]
When the designated continuous data does not exist on the data storage device 12 and is read from the archive device 15 (S1YES, S3YES), the central controller 16 instructs the archive device 15 to copy which part of the continuous data to which buffer storage device 17. (S4, S5). The archive device 15 reads the specified continuous data and writes it to the specified buffer storage device 17. When the writing is completed, the archive device 15 notifies the central control device 16 of the completion. Thereafter, the central control unit 16 sends the data written to the buffer storage device 17 by the archive device 15 to the data storage control device 11 connected to the data storage device 12 to which the read continuous data is written. (S6). Steps S5 and S6 are repeated until the processing for the requested continuous data is completed.
[0033]
Here, when continuous data is instructed based on an access request from the user, the continuous data read from the archive device 15 is written to the buffer storage device 17 (S4, S5) and also to the main storage device 13. And transmitted to the user via the communication control device 14.
[0034]
When writing the continuous data stored in the data storage device 12 to the archive device 15 (S1YES, S3NO), the continuous data flows on the reverse route (S7, S8, S9).
[0035]
Each of the data storage control devices 11 in FIG. 1 may be configured as shown in FIG. In other words, a plurality of data storage control units 101 that perform reading and writing from the corresponding data storage devices 12 may collectively constitute one data storage control device 11.
[0036]
As shown in FIG. 4, the archiving apparatus includes a plurality of recording media 27 and shelves 26 for storing the recording media 27, a driving device (also referred to as a drive) 24 for reading and possibly writing continuous data recorded on the recording media, And a control device 25 for controlling the driving device and the robot device. The recording medium is specifically an optical disk, a magneto-optical disk, a magnetic tape, or the like. The control device manages which continuous data is stored in which storage medium, determines which recording medium is read or written by which drive according to the access request, and mounts the necessary recording medium on the drive by the robot. Instruct the device. Further, it has a function of sending continuous data read by the drive device to the requesting computer (bus 20, bus 21), and a function of writing continuous data sent from the request source computer (bus 21) by the drive device. .
[0037]
(Specific example 2)
An example of another embodiment of the present invention is shown in FIG.
In the continuous data server device of this example, the data storage control device 11, the communication control device 14, and the buffer storage device 18 are connected as shown in FIG. That is, for each combination of all the data storage control devices 11 and all the communication control devices 14, the data storage control device 11 and the buffer storage device 18 connected to the communication control device 14 are provided. This set of buffer storage devices 18 plays a role corresponding to the main storage device 13 in FIG. 1, but with such a configuration, between any data storage control device and any communication control device, A dedicated buffer storage device for passing continuous data can be provided, and a data path (19) between the data storage control device and the buffer storage device and a data path (22) between the buffer storage device and the communication control device can be provided. Both are multiplexed, and the data transfer capability of the data path can be increased. This configuration is described in detail in Japanese Patent Application No. 7-29749.
[0038]
In this example, in addition to this configuration, a buffer storage device 17 connected to the data storage control device 11 and the archive device 15 is provided for all combinations of the archive device 15 and each data storage control device 11. With such a configuration, a dedicated buffer storage device used to transfer continuous data between the archive device and any data storage control device can be provided between the archive device and the data storage control device. The data path (19) is multiplexed, and the data transfer capability of the data path can be increased. In addition, continuous data can be transferred between the archive device and the data storage control device without affecting the continuous data distribution process from the communication control device.
[0039]
The way of using the buffer storage device 17 in the continuous data server device of FIG. 5 is the same as that shown in FIG. 3, and the central control device 16 writes which part of which continuous data to which buffer storage device 11 to the archive device 15. To indicate. The archive device 15 reads the designated continuous data and writes it to the designated buffer storage device 11. When the writing is completed, the archive device 15 notifies the central control device 16 of the completion. Thereafter, the central control unit 16 sends the data written to the buffer storage device 17 by the archive device 15 to the data storage control device 11 connected to the data storage device 12 to which the read continuous data is written. To write to the specified location.
[0040]
When writing the continuous data stored in the data storage device 12 to the archive device 15, the continuous data flows through the reverse route.
The configuration of the archive device 15 is the same as that shown in FIG.
[0041]
【The invention's effect】
As described above, by using the continuous data server device of the present invention, continuous data can be distributed without reducing the number of continuous data that can be distributed at the same time even when reading from or writing to the archive device. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a continuous data server device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a conventional continuous data server device.
FIG. 3 is a flowchart showing an operation procedure of the central control device of the embodiment.
FIG. 4 is an exemplary view showing a configuration example of an archive device of the embodiment.
FIG. 5 is a diagram showing a configuration example of a continuous data server device according to another embodiment of the present invention.
FIG. 6 is a diagram showing another configuration example of the data storage control device.
[Explanation of symbols]
10, 16 ... central control device 11 ... data storage control device 12 ... data storage device 13 ... main storage device 14 ... communication control device 15 ... archive devices 17, 18 ... buffer storage devices 19, 20, 21, 22 ... bus 23 ... Robot device 24 ... Drive device 25 ... Control device 26 ... Shelf 27 ... Storage medium

Claims (2)

The first bus,
  A main storage device connected to the first bus;
  A communication controller connected to the first bus and outputting continuous data to an external communication path;
  An archive device capable of storing continuous data and reading out desired continuous data;
  A second bus independent of the first bus for transferring continuous data read from the archive device;
  A plurality of buffer storage devices for temporarily holding continuous data from the second bus;
  A plurality of data storage devices for storing continuous data;
  The first bus, one of the data storage devices, and one of the buffer storage devices are connected, and continuous data is read from the connected data storage device, and the main memory is read via the first bus. A means for directly transmitting data to the device or the communication control device without passing through the buffer storage device; and a means for reading continuous data temporarily stored from the connected buffer storage device and writing the data to the data storage device. A continuous data server device comprising a plurality of data storage control devices. The first bus,
  A main storage device connected to the first bus;
  A communication controller connected to the first bus and outputting continuous data to an external communication path;
  An archive device capable of storing continuous data;
  A second bus independent of the first bus for transferring continuous data to be written to the archive device;
  A plurality of buffer storage devices for temporarily storing continuous data to be written to the archive device via the second bus;
  A plurality of data storage devices for storing continuous data;
  The first bus, one of the data storage devices, and one of the buffer storage devices are connected, and continuous data is read from the connected data storage device, and the main memory is read via the first bus. Means for directly transmitting to the device or the communication control device without passing through the buffer storage device, and reading continuous data from the connected data storage device and writing continuous data for temporary holding in the buffer storage device And a plurality of data storage control devices each having a means.

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