JP2541512B2 - Disk controller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk controller, and more particularly to a disk controller suitable for computer networks.

[0002]

2. Description of the Related Art In recent years, LAN (Local Area)
Networking of computers such as Network) is progressing, and it is becoming common to provide a large-capacity disk device in the network for the purpose of data sharing and effective use.

Therefore, a disk controller for efficiently executing I / O processing (writing processing and reading processing) from each computer (host) becomes important.

As shown in FIG. 5, the conventional disk control device measures a plurality of host interfaces 60 for controlling communication with a plurality of hosts and a time when an I / O processing request from the host is received. Shared timer 54
And a shared memory 52 that stores the host interface number and the arrival time in the order of arrival, and the arrival time of the I / O processing request received via the host interface 60 is detected by the shared timer 54 and stored in the shared memory 52. In addition, a plurality of directors 51A, 51B, 51C and 51D for executing I / O processing to the disk device 66 based on the stored contents 53 of the shared memory 52 are provided.

Next, the operation of the above conventional example will be described.

(1). When the director 51A receives an I / O processing request from the host via the host interface 60, the director 51A checks whether the disk device 66 is in use.

(2). When confirming that the disk device 66 is not in use, the first director 51A executes an I / O process for the disk device 66.

(3). Here, the second director 51B
However, when the I / O processing request is received via the host interface 60, the second director 51B detects the arrival time of the I / O processing request with the shared timer 54 because the disk device 66 is in use. At the same time, the host interface number is stored in the shared memory 52.

(4). The first director 51A is
When the O processing is completed, the I / O processing request stored in the shared memory 52 and having the earliest arrival time is waiting for the I / O processing request.
I / O processing request and search for the director (here, the second
Control to the director 51B).

(5). The second director 51B executes the standby I / O processing for the disk device 66.

[0011]

However, in the above-mentioned conventional example, the host interface number and the arrival time at which the waiting I / O processing request is received are stored in the shared memory as one set of waiting information. The inconvenience that a large storage area of at least "the number of connected hosts-1" sets must be secured in the shared memory, and the load of the control device increases due to the writing process of the standby information to the shared memory. was there.

Further, when deciding the I / O processing to be executed next from the waiting I / O processing, all the waiting information stored in the shared memory must be compared, and the decided I / O Since the standby information for the process must be deleted from the shared memory, there is a problem that the processing time until the next I / O process is executed is long.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a disk controller which improves the disadvantages of the prior art and has a short waiting time even when I / O processing requests compete.

[0014]

Therefore, according to the present invention, a plurality of directors that control I / O requests from a plurality of hosts to execute I / O processing with a disk device, and a plurality of directors shared by these directors. And an exclusive control means for waiting for I / O processing from the host when a plurality of directors are in an occupied state in which I / O processing of the disk device is being performed by other directors. Each has.

Moreover, when a plurality of directors receive the I / O request from the host and the disk device is occupied, the order of the directors of the other directors is stored in the shared memory as an inter-director order table. Inter-director sequence control means for selecting the director whose standby time is the longest by the inter-director sequence table when the exclusive state is released by the exclusive control means. With the function to hand over the disk operation right to the director,
The configuration is adopted. This aims to achieve the above-mentioned object.

[0016]

During operation of the disk controller, the director executes I / O processing with the disk device in response to I / O requests from a plurality of hosts. At this time, the exclusive control means receives the I / O from the host when in the occupied state where the I / O processing of the disk device is being performed by another director.
Wait for O treatment. Since the directors operate independently, a shared memory shared by a plurality of directors is used for communication between the directors.

The inter-director order control means stores the order of its own director with respect to other directors in the shared memory as the inter-director order table when the disk device is occupied when the I / O request from the host is received. To do. This is because the I / O request is the earliest request for the disk device, so that the director who has received the I / O request is ranked last for other directors that are already waiting. I have to. Therefore, the inter-director order table is updated so that the order of its own director is the last with respect to other directors.

Further, the inter-director order control means selects the director whose waiting time is the longest by the inter-director order table when the exclusive state is released by the exclusive control means, and transfers the disk operation right to the director. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of a disk control device according to this embodiment. Disk controller 10
Are shared by the plurality of directors 1A, 1B, 1C, 1D that execute I / O processing with the disk device 26 in response to I / O requests from the plurality of hosts 20, 21 ... An exclusive control unit 2A that includes a memory 4 and that causes the director 1A to wait for I / O processing from the host 20A when the director 1A is in an occupied state in which I / O processing of the disk device 26 is being performed. Is equipped with. This exclusive control means 2A, 2
B, 2C, 2D, for example, when the disk device 26 is occupied during the I / O processing from the host 21A, I / O requests from the other hosts 21B, 21C, etc. to the other directors 1B, 1C, 1D. Even if there is, it is controlled to wait.

Further, the director 1A is the host 20A.
If the disk device 26 is occupied when the I / O request is received from the other director 1 in the shared memory 4.
The inter-director order control means 3A for storing the order of the own director 1A for B, 1C and 1D as the inter-director order table 5 is provided.

The inter-director order control means 3A has a low priority order for starting the I / O processing of its own director 1A with respect to all other directors 1B, 1C and 1D in the inter-director order table 5 read from the shared memory 4. It has a function of updating the inter-director order table 5 as having a relationship. That is, the director order control means 3A,
3B, 3C and 3D are I / Os from the hosts 20, 21 ...
When a request is made, the other director 1 drives the disk device 2
When it occupies 6, the inter-director order table 5 is read from the shared memory 4, the own director is set to the end, and the inter-director order table 5 is updated.

Sequence control means 3 between the plurality of directors
A, 3B, 3C, 3D, director 1B is host 21
When the exclusive state is released by the exclusive control means 2B after the I / O processing for B is completed, the director 1A, which has the longest waiting time, is selected based on the inter-director order table 5, and the director 1A is selected. It is equipped with a function to hand over the disk operation right.

FIG. 2 is an explanatory view showing the order relation between the directors. Here, A to D are provided from the first node A to the fourth node D. A and B are represented by an arrow a as shown when A has priority. A is B
Since there is an I / O request waiting for both A and B, the I / O request of A is processed first. In the illustrated example, since arrows a, c, and d are gathered in A, A has priority over all other nodes. Then
Since arrows d and e are gathered in B and A is prioritized between A and B, B is prioritized after A. Since arrow f is heading to C, C has priority over B. In this way, when the nodes to be processed are arranged in order, A, B, C, D
It becomes the order relation.

In this embodiment, the direction of the arrow is represented by "1" with the order relation shown in FIG. 2 as an initial setting. If there is an order relation opposite to the direction of the arrow of this initial setting, it is expressed by "0". For example, in the case of A and B, when B has priority, the arrow a becomes “0”. In the case of B and C, when B has priority, the arrow d is “1” because it has the same order relationship as in the initial setting.

As described above, when the director is a node, the order relation of all directors 1 with other directors 1 can be expressed by 2 [bits]. Therefore, if the number of directors is N, then N (N-1) / 2
The inter-director order table 5 can be formed by the bit pattern table of [bit].

FIG. 3 is a chart showing the order between directors and the bit pattern data corresponding thereto. As shown in FIG. 2, assuming that the directors A to D obtain the disk operation right in the order of A, B, C, and D, the arrows a to f indicate “111”.
111 ". At this time, I
/ O occurs, director A
The I / O processing is executed after confirming that the C / D I / O is not executed. Since the I / O is not in the standby state, the bit table does not change.

Next, when an I / O is generated in the director B, this I / O is being processed by the director A.
Wait for O. Disk device 2 by another director A
Since director 6 is occupied, director B has an order relation a, of its own director B with respect to the other directors A, C and D.
Record d and e in the director order table 5. At this time, the director B updates the inter-director order table on the assumption that the priority order of the I / O processing start of the own director B is lower than the other directors A, C, and D.
That is, the order relation a, d, e of the director B is set to "1,
It is controlled to give priority to I / O processing in other directors as "0, 0".

Since the priority of A over director B is the same as the initial setting, the order a between directors is "1", and the priority of C over director B is the opposite direction from the initial setting, so The order d becomes "0",
Similarly, the order e between directors is also "0". This is because, since the I / O request generation of the director B is the latest, when another director is already waiting for I / O, the subsequent sequence is taken as its own order. Further, the director B updates the order relation between the director B and the other directors A, C, and D, and does not change the priority order such as A-C, which has no relation with itself. Further, here, processing is performed regardless of whether or not another director is executing I / O.

The director B changes the arrows a, d and e to "1,
Since it has been updated as "0, 0", the director order table becomes "111001", and the director order at this time becomes "A, C, D, B" in descending order of priority (FIG. 3). In this way, the director that has received the latest I / O request controls the order of its own director to be the last.

Next, the director A is executing I / O,
I / O to director C while director B is waiting for I / O
When occurs, the director C performs the following processing.
The director C updates the inter-director order table so that the other directors are in the last order from themselves. That is, in the arrows shown in FIG. 2, b, d, and f are changed to "1,
"111001" is changed from "111001" which was updated by the director B immediately before the change to "1,0".
Then, in this bit pattern, the order is “ADBC”.

In this way, the disk operation right is given to the director B, which has generated the I / O request earlier, than to the director C, which has generated the I / O request.

FIG. 4 is a block diagram showing the detailed structure of the director 1A. Director 1A uses multiple hosts 20
The host-to-host order control means 6A for generating the host-to-host order table 8A from the I / O request reception order and the director internal memory 7A for storing the host-to-host order table 8A. Further, the host-to-host sequence control means 6
When A is waiting for an I / O request from one host 20A in the same director 1A and there is an I / O request from another host 21A, the director directs the inter-director sequence control means 3A. It has a function of prohibiting the update of the inter-sequence table 5.

In this embodiment, four directors 1A, 1B, 1C and 1D are connected to one disk device 26. One director 1 has four hosts 20, 21, 22, 22 via four host interfaces.
23 is connected.

Here, the inter-host sequence table 8 is shown in FIG.
And the bit pattern shown in FIG.

The example shown in FIG. 3 will be described again. As shown in FIG. 3, the bit pattern is initially set to "1111" in the initial setting.
11 ", the order between directors is ABCD. Next, I / O from the host interface 20A shown in FIG.
When the director A receives the O request and the other directors 1B, 1C, 1D do not occupy the disk 26, the I / O request from the host 20A is processed. Since the I / O request from the host 20A does not enter the standby state, the inter-director order table 5 is not changed.

Next, the host 2 by this director A
When the director B receives the I / O request of the host 20B during the I / O processing of 0A, the exclusive control unit 2B waits for the I / O request of the host 20B. Further, the inter-director order control means 3B reads the inter-director order table 5 from the shared memory 4 and sets the order of the director B to the end. Then, the inter-director order table 5 becomes "111001" and the order of priority is ACDB.

Further, when the director 1C is processing the I / O of the host 20A and the director 1B is waiting for the I / O request of the host 20B, the director 1C receives the I / O request from the host 20C. The 1C waits for the I / O request from the host 20C and updates the inter-director order table to "111100". Then, the order of priority becomes the order of ADBC.

Here, a case where there is an I / O request from the host 21B while waiting for I / O from the hosts 20B and 20C will be described. First, host 20B and host 21B
The method of setting the priority order and the method of creating the inter-host order table 8C are the same as those between directors. However, the director B sets the inter-director order table 5 to the host 2
If it is updated based on the I / O wait from 1B, it will be in a very unfavorable state. That is, when the director B sets itself at the end, the order relation is correct in the relation between the process from the host 21B and the host 20C, but the host 20
The order of the relationship between B and the host 20C is reversed.

Continuing with the example shown in FIG.
If “a, d, e” is set to “1, 0, 0” in the same process, the inter-director order table 5 becomes “111000”, the director C has priority over the director B, and the AD
It will be in the order of CB. Therefore, when the hosts 20, 21, 22, and 23 compete on the same director in this way, the inter-director order table 5 is not updated at the time of the second and subsequent I / O requests.

The inter-host sequence control means 6A is a director when an I / O request from one host 20A in the same director 1A is waiting and when an I / O request is made from another host 21A. Since the inter-director order control means 3A is prohibited from updating the inter-director order table, each director is given equal processing opportunities.
It produces the same effect as the round robin method.

Next, when the I / O of the host 20A is completed, the exclusive control means 2A in the director 1A releases the occupied state of the disk device 26. In response to this, the inter-director order control means 3A reads out the inter-director order table 5 from the shared memory 4, reads out from "111100" that the priority order of the director is "ADBC", and I / O the director 1A. Since there is no request, control is transferred to director 1D. Further, since the director 1D has no I / O request, control is transferred to the director 1B. Alternatively, the inter-director order table 5 may be updated so that the inter-director order of the disk device 26 is at the end when the I / O processing to the disk device 26 is completed. In that case, control is transferred to the director 1D regardless of the presence / absence of an I / O request in the director 1A.

In the director 1B, the inter-host sequence control means 6B selects the host 20B to be processed first and executes the relevant I / O to the disk device 26. further,
The exclusive control means 2B brings the disk device into an occupied state by the I / O processing of the host 20B.

Further, the directors 1A, 1 other than the director 1C currently waiting for the I / O of the host 21C
When an I / O request is issued to D, each director 1
A and 1D update the inter-director order table 5.

In the director 1B, the I / O of the host 20B
When the O process ends, the inter-director sequence control means 3B
Transfers control to director 1C based on inter-director order table 5. The director 1C executes the process of the standby host 20C.

After completion of the I / O processing of a director 1,
As for a method of transferring control to another director 1, for example, each director may access the shared memory 4 in order at a regular cycle, and the shared memory 4
In addition, a flag indicating the occupied state of the disk and a flag indicating the director having the operation right may be stored. In this case, after the I / O processing of a director is completed, the exclusive control means 2 changes the flag indicating the occupied state of the disk to a flag meaning release, and the inter-director sequence control means 3 changes the inter-director sequence. The flag indicating the director having the operation right may be updated based on the table 5.

As described above, according to the present invention, the inter-director sequence table 5 for I / O processing between a plurality of directors,
The host-to-host sequence table for I / O processing between multiple host interfaces in the director is stored in the shared memory and the memory in each director only with simple bit information. The standby I / O processing can be reliably controlled without requiring the standby information storage area, and the standby I / O between directors can be performed.
The order control of the I / O processing can also be controlled in a pseudo manner (certainly according to the condition) by only accessing the shared memory several times, and thus the overhead of the processing for determining the order of the I / O processing to be executed next is reduced. , The throughput is improved.

[0048]

Since the present invention is constructed and functions as described above, according to this, since the standby information stored in the shared memory is represented by only simple information, it is possible to secure a small area of the shared memory and It is possible to provide an unprecedented excellent disk control device in which the number of times of accessing the shared memory is reduced, the overhead of determining the I / O processing to be executed next is reduced, and the throughput of the I / O processing is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a method of generating an inter-director order table shown in FIG.

FIG. 3 is a table showing details of an inter-director order table shown in FIG.

FIG. 4 is a block diagram showing a detailed configuration of a director shown in FIG.

FIG. 5 is a configuration diagram showing a conventional example.

[Explanation of symbols]

A Nodes A to D First to fourth nodes 1 Directors 1A to 1D First to fourth directors 2 Exclusive control means 2A to 2D First to fourth exclusive control means respectively possessed by the first to fourth directors 3 inter-director sequence control means 3A to 3D First to fourth inter-director sequence control means respectively possessed by first to fourth directors 4 shared memory 5 inter-director sequence table 6 inter-host sequence table 6A to 6D 1 to 1 The first to fourth inter-host sequence tables of the four directors 7 Director internal memories 7A to 7D The first to fourth director internal memories of the first to fourth directors 8 Inter-host sequence tables 8A to 8D First to fourth host-to-host sequence tables that the first to fourth directors respectively have 20 Host (host interface) 20A-20D 1st host in 1st-4th directors 21A-21D 2nd host in 1st-4th directors 22A-22D 3 in 1st-4th directors Th host 23A-23D 4th host with 1st to 4th directors

Claims (5)

(57) [Claims] 1. A plurality of directors for controlling I / O requests from a plurality of hosts to execute I / O processing with a disk device, and a shared memory shared by the plurality of directors, I / O from the host when a plurality of directors are in an occupied state where I / O processing of the disk device is being performed by another director
In the disk control device, each of which has an exclusive control means for making a process stand by, the shared memory is provided when the plurality of directors are in the occupied state when the disk device receives an I / O request from the host. Is provided with inter-director order control means for storing the order of its own director with respect to other directors as an inter-director order table, and when the exclusive control means releases the exclusive state, the director inter-order order control means A disk control device having a function of selecting a director whose waiting time is the longest by an inter-sequence table and handing over the disk operation right to the director. 2. The plurality of inter-director order control means have a lower priority order of starting their own I / O processing with respect to all other directors in the inter-director order table read from the shared memory. 2. The disk control device according to claim 1, further comprising a function for updating the inter-director order table. 3. The inter-director order table holds an order relation between all directors and other directors.
3. The disk control device according to claim 1, wherein the disk control device is formed of a bit pattern table expressed in [bit]. 4. The inter-director order control means sets the order relationship between the directors to "1" according to the priority order in the initial state between the directors, and the order between the directors is opposite to the order in the initial state. "0" when it becomes an order
4. The disk control device according to claim 3, further comprising a function for updating the bit pattern table. 5. An inter-host order control means for generating a host-to-host order table from the plurality of host I / O request receiving orders, and a director internal memory for storing the host-to-host order table. The host-to-host sequence control means, when the I / O request from the one host in the same director is on standby, when there is an I / O request from another host, 3. The disk control device according to claim 2, further comprising a function of prohibiting the order control means from updating the inter-director order table.