JPH0573485A - Data transfer control system - Google Patents

Abstract

PURPOSE:To avoid an insignificant data transfer instruction, and to curtail an overhead by constituting the system so that a controller manages and grasps a data transfer state of both a host device side and a storage device side. CONSTITUTION:Each storage device 202 is provided with a sub-processor 212 (one set in each storage device 202) for executing a data transfer between a controller 201 and a drive buffer 207, and a sub-processor 213 for executing a data transfer between the drive buffer 207 (having a storage area divided at every disk drive 208) and the disk drive 208, and constituted of the drive buffer 207 for storing temporarily data transferred by the sub-processors 212 and 213, and a processor 206 for managing a data transfer state, etc., of the storage device 202. In such a state, by the sub-processors 212 and 215, the data transfer is executed independently, respectively, based on a data transfer instruction of the processor 206.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores data transferred from a host device in a plurality of storage media (disk drive, etc.).
On the other hand, the present invention relates to a data transfer control method in an input / output device for writing and reading, and particularly to a data transfer control method having a plurality of disk devices for realizing high-speed data transfer.

[0002]

2. Description of the Related Art Generally, in a computer system, the transfer speed of a disk device (disk drive) has not caught up even though the processing performance of the CPU has been greatly improved. Since the CPU has to wait a long time until data is written on the disk and the processing time becomes long, the user also uses the cost for wasteful processing. Engineers who build the system are trying to avoid this problem by adding cache memory, etc., but this is not a sufficient measure. For this reason, it is desired to improve the data transfer rate for a disk device (disk drive) and operate at a higher multiplexing.

A disk array is represented by a high-speed data transfer device, and is disclosed in, for example, JP-A-62-24481.
In the technology disclosed in Japanese Patent Publication, a plurality of storage devices having buffers for temporarily holding input / output data are provided, and input / output operations are simultaneously performed on the plurality of storage devices. A sufficient transfer rate is maintained so that data always exists in this buffer, and the data transfer process is not interrupted between the disk control device and the storage medium (disk drive) to speed up the data transfer.

On the other hand, with regard to the multiple processing, the above-mentioned Japanese Patent Laid-Open No. 62-62160
Although not described in Japanese Patent No. 244481, for example,
"Separate Volume Interface Latest SCSI Manual (198
As described in "9.2.1 Issue CQ Publisher"), in general, when the data transfer with the storage device is started, the data transfer path is completed until the amount of data transfer processing requested by the control device is completed. Data transfer to another storage device that is exclusively used by the storage device and connected to the same data transfer path is started after the data transfer path is released.

[0005]

In the above-mentioned prior art, the buffer is guaranteed not to be in an empty state at the time of writing the data, and is guaranteed not to be full at the time of reading the data. The data transfer operation between the drive and the drive (disk device) is characterized by continuous transfer without interruption.

However, the present inventors have found that the above-mentioned prior art has the following problems.

That is, in the above-mentioned conventional technique, it is necessary to have a sufficient transfer rate capable of continuous data transfer operation between the buffer and the drive, but the state of the upper device side or the storage device side (disk drive side) Changes dynamically (for example, when the data transfer speed on the host device side and the storage device side (drive side) differs, or changes due to error recovery, etc.), the transfer status changes and the data transfer operation is interrupted. The situation that must be done is to occur.

For example, when the writing process is performed when the transfer speed on the host device side is slower than the transfer speed on the storage device (drive) side, the data temporarily stored in the buffer will eventually become empty, When the read process is performed, the data temporarily stored in the buffer will eventually become full, and the data transfer operation must be interrupted on both the host device side and the storage device side (drive side). ..

The reason why the data transfer operation must be interrupted in this way is that there is a difference in the data transfer speed between the host device side and the storage device side. In order to eliminate this data transfer speed difference, in the case of the above example, the control device receives a plurality of I / O requests from the host device, and a plurality of volumes are respectively stored in a plurality of storage devices (drives).
It is conceivable to improve the data transfer efficiency to the drive by performing simultaneous transfer to the drive. However, in this method, when data transfer is started by collecting each volume, a single data transfer path between the control device and the storage device (drive) is dedicated to the volume, and therefore, only once. If the amount of data transferred is a large amount of several megabytes, simultaneous transfer to multiple volumes cannot be performed.

Therefore, the inventors of the present invention first set one or a plurality of blocks (logical blocks) for one data transfer amount.
By dividing into a single transfer path,
I thought about enabling a substantially simultaneous transfer.

The present inventors further connect a plurality of storage media (disk drive devices) to one storage device in order to eliminate the influence of the above-mentioned difference in transfer speed, and use the disk drive device in the storage device. In addition to providing a drive buffer for each device, a channel buffer for data transfer with the host device is provided in the control device, and both buffers are connected by a single data transfer path, so that both buffers are fully occupied. I thought to alleviate the condition. However, in this case, if the control device does not always manage the data transfer statuses of both the upper device side and the storage device side (including the empty state of these buffers), for example, the control device may transfer the data transfer to the storage device side. Even if an instruction is given, a meaningless (wasteful) transfer instruction may occur, such as a response from the storage device side indicating that the transfer cannot be performed.

Accordingly, one object of the present invention is to solve the above-mentioned problems of the prior art, in which the control device manages the transfer status of both the upper device side and the storage device side and makes senseless data for the storage device. It is to provide a data transfer control method that suppresses the generation of a transfer instruction and improves the processing efficiency of operations related to data transfer.

Another object of the present invention is, when a data transfer instruction is issued to a plurality of storage media connected to one storage device, a storage medium to be instructed next is determined according to the transfer status to determine a single data path. Even so, the object of the present invention is to provide a data transfer control method that improves the efficiency of data transfer processing for a plurality of storage media.

[0014]

In order to achieve the above object, in the data transfer system of the input / output device of the present invention,
As a basic configuration, the control device has the following functions. That is, the control device provides information indicating whether or not the storage medium can execute the next data transfer request (data transfer executability information) as data of one or more blocks (logical block) for the storage medium. A storage medium that receives data from a storage device for each transfer (for example, as a format added to the completion report for each data transfer) and manages this by the control device so that the storage medium to which the data is transferred next can be transferred. It is equipped with a means for selecting from the medium.

Specifically, according to the present invention, one or a plurality of storage devices having a drive buffer for temporarily holding data and connected to one or a plurality of storage media (disk drives), and the data are temporarily stored. In a data transfer method of an input / output device, which has a control device having a channel buffer held in a unit and integrally managing the storage device, and a single data transfer path connecting between the control device and the storage device, When data is transferred between the control device and the storage device, the control device controls the storage device (this data) from the storage device every time one or more data blocks are transferred between the channel buffer and the drive buffer. By receiving the information on the feasibility of data transfer regarding the next data transfer in the storage medium to which the block has been transferred) It recognizes the data transfer state of the position device side and the storage device side both configured to perform the Supporting connexion next data transfer on the recognition result.

Further, the control device manages the received information on whether or not the data transfer can be executed, and based on this information, determines the storage medium for the next data transfer. In this case, as a result of checking the management information (managed data transfer executability information), when there is no storage medium that can transfer data next time, the data transfer request is canceled and a report that the data can be transferred from the storage medium is reported. A means for resuming after waiting for (data transfer resumption notification) is provided.

Further, the control device divides the input request received from the host device into a plurality of data requests, and transfers data to one or a plurality of storage media between the channel buffer and the drive buffer. To configure.

[0018]

The operation based on the above configuration will be described.

According to the present invention, the control device uses the data transfer availability information received in the previous data transfer,
Since the data transfer statuses of both the upper device side and the storage device side are known in advance, even if one of the transfer states changes during data transfer, this should be done in advance before instructing the next data transfer request. Since the storage medium that can be surely known and the data transfer can be always selected as the next request, the instructed data transfer request is meaningless (useless) data transfer depending on the state of the storage device or the storage medium. It is possible to reliably prevent the instruction.

When the data transfer is disabled,
Effective multiplex data transfer control can be performed by selecting another storage medium capable of data transfer.

Further, the input / output request received from the host device is divided into a plurality of data requests (logical blocks), and data is transferred between a plurality of media between the channel buffer and the drive buffer. The transfer efficiency can be improved by enabling a substantially simultaneous parallel transfer through a single transfer path.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A data transfer control system according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an input / output device which is an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the configuration of an information processing system including the input / output device of this embodiment.
3 is a conceptual diagram of the data flow in this embodiment, FIG. 4 is a basic control sequence between the control device and the storage device in this embodiment, FIG. 5 is a multiplex control sequence between the control device and the storage device in this embodiment, FIG. 6 is a flow chart showing the data transfer instruction issuing procedure in this embodiment.

First, an example of the overall configuration of the input / output device of this embodiment and the configuration of an information processing system using the same will be described with reference to FIGS.

The information processing system according to the present embodiment includes, for example, a central processing unit that forms the center of a general-purpose computer system,
Instead of the central processing unit, a host device 10 including a channel or the like for controlling the exchange of data with the outside.
0 and an input / output device 200 for storing and reading information exchanged with the host device 100. FIG. 1 shows an example of the overall configuration of the input / output device 200. As shown in FIG.
The inside of 00 is composed of a plurality of storage devices 202 for writing and reading data, and a control device 201 for centrally managing these storage devices 202.

The control device 201 includes a plurality of host devices 100.
And a sub processor 210 (corresponding to each host device) that transfers data between the host device 100 and the channel buffer 203 for each connection path, and has a sub processor 211 (each host device) that transfers data between the channel buffer 203 and the storage device 202. One channel buffer 203 (corresponding to the storage device 202), which temporarily stores data transferred by the sub-processors 210 and 211 (the storage area is divided corresponding to the number of drives 208, and these divisions are performed). The shared area is commonly used by each host device), one processor 204 that manages the data transfer status of the host device 100 side, and one processor 205 that manages the data transfer status of the storage device 202 side. It is configured. The sub-processor 210 and the sub-processor 211 perform data transfer independently of each other in response to a data transfer instruction from the processors 204 and 205.

On the other hand, each storage device 202 is connected to the control device 20.
Data transfer between the sub-processor 212 (one in each storage device 202), the data transfer between the drive buffer 207 (having a storage area divided for each disk drive 208) and the disk drive 208. A drive buffer 207 for temporarily storing the data transferred by the sub-processors 212 and 213, and a processor 206 for managing the data transfer status of the storage device 202.
It is composed of In the illustrated example, one storage device 20
There are four sub-processors 213 in the unit 2, and four disk drives (independent disk drive devices) 208 are connected to each sub-processor 213. Sub-processor 212 and sub-processor 213
In accordance with the data transfer instruction of the processor 206, the data transfer is independently performed.

In the case of the write processing, the data transferred from the host device is temporarily stored in the channel buffer 203, and the channel buffer 203 drives the drive buffer 20.
Written to each drive via 7. Further, in the case of the read processing, a large amount of data read from the drive is stored in the temporary drive buffer 207, and the drive buffer 2
From 07, it is transferred to the upper device via the channel buffer 203.

FIG. 3 shows a data flow in the input / output device 200 shown in FIG. FIG. 3 shows an example of the writing process, and shows a state in which four disk drives 208 (one for each sub-processor 213) are operating in multiplex. Note that only one sub-disk drive 208 can be operated by one sub-processor 213 at a time. In the input / output device 200 shown in this embodiment, the channel buffer 203 and the drive buffer 207 are divided into a plurality of planes and used, and the sub-processor 210, the drive or the drive group (in this example, 4 2 disk drives
By providing the sub-processor 213 for each 08), it is possible to receive data from the host and write data to the drive in response to a plurality of input / output requests.

On the other hand, data transfer between the channel buffer 203 and the drive buffer 207 is performed by the sub processor 211.
The sub-processor 212 has only one data transfer path, and in order to perform effective multiplex processing,
How to use this one data transfer path is an important point. In the present embodiment, the method described below is used to prevent the generation of meaningless data transfer requests even with a single data transfer path and realize an effective multiple data transfer operation.

The channel buffer 203 in this embodiment.
The data transfer between the drive buffer 207 and the drive buffer 207 is performed in the sequences 401 to 404 shown in FIG. The data transfer between the channel buffer 203 and the drive buffer 207 issues a data transfer request from the sub processor 211 to the sub processor 212 (411), then data transfer is performed (412), and the amount of data specified by the data transfer request is transferred. When the transfer is completed, the sub processor 212 reports the end to the sub processor 211 (413).

One feature of this control sequence is that, in addition to the data transfer result (normal / abnormal) just performed, information indicating whether the next data transfer is feasible or not is added. The next data transfer information allows the control device 201 to know the data transfer status of the storage device (the disk drive). The sub-processor 211 recognizes the storage status of the drive buffer 207 based on the next data transfer information, further matches the storage status of the channel buffer 203, and manages the data transfer status of both sides to determine whether the next data transfer can be executed or not. Can be easily determined. A table for managing this is the data transfer management table 450. In this embodiment, this data transfer management table is managed on the processor 205.

In FIG. 4, since the completion report 423 of the second data transfer sequence 420 reports that the next data transfer cannot be executed, the sub processor 211 judges that the data transfer of the disk drive cannot be executed, and suspends the data transfer request. , The data transfer is restarted while waiting for the transfer restart request 424 from the sub-processor 212.

Another characteristic of this control sequence is that the input / output request from the host device 100 is divided into a plurality of data transfer requests so that the data can be transferred to the plurality of disk drives 208 substantially simultaneously, and the sub-processor 211 and the sub-processor 212 are divided. The point is that data is transferred between them. For example, if the data transfer amount instructed by the upper level device 100 is 16
In the case of K bytes, in FIG. 4, one data transfer amount between the sub-processors 211 and 212 is transferred as 4 K bytes, and a total of four data transfer requests are made and completed. In this way, by dividing the data into a plurality of data transfer requests and performing data transfer between the channel buffer 203 and the drive buffer 207, the control device 201 side is given an opportunity to judge the data transfer status, and the drive during data transfer is When transfer cannot be executed, one data path can be effectively used by issuing a data transfer request to another disk drive. The method of selecting another disk drive can be easily realized by managing the above-mentioned data transfer management table for each disk drive 208.

In FIG. 4, in order to explain the basic concept of the control sequence, the input / output request from the host device 100 is 16K.
Although described as bytes, the effect of the present data transfer control method is sufficiently exerted in the case of large capacity data transfer of several megabytes to several tens of megabytes. Because the host device 1
00 side and the storage device 202 side physically have a difference in data transfer rate, or during the data transfer, the storage device 20
2, or if the disk drive 208 goes into error recovery, the channel buffer 203, the drive buffer 2
This is because 07 will eventually become an empty state or a full state.

FIG. 5 is a diagram showing how data is transferred between the channel buffer 203 and the drive buffer 207 for a plurality of drives. In this example, the sub-processor 211 manages the data transfer status of the four drives “0” to “3” as the disk drive 208, and the result of the data transfer request to the drive “0” (50
1) Since a report indicating that the next data transfer cannot be executed is received (502), the sub-processor 211 selects an executable drive "1" from the data transfer management table and makes a data transfer request (503). The restart of data transfer to the drive “0” is suspended until a data transfer restart request is received from the sub processor 212, and data transfer is performed to another drive capable of data transfer during this period (504, 50).
5). Figure 5 shows drive "0" from sub-processor 212
To the drive “0” again (507), and the information that the next data can be transferred is received (508). However, the next data transfer request is sent to the drive 1 (509). This is suspended because there is no data that can be transferred to the drive "0" in the channel buffer 203.
The data transfer to the drive “0” is resumed after the transfer data is stored in the channel buffer 203 and then added to the schedule as a data transferable drive.

In FIG. 6, the processor 205 is the processor 20.
6 is a flow chart showing the procedure from the time when the completion report for the data transfer request is received from 6. Processor 20
The processor 5 grasps the data transfer state of the storage device 202 side by the information for the next data transfer request added by the processor 206 to the end report, checks this and the state of the control device 201 side, and determines the next data transfer request. Decide what to do for the drive. That is, the processor 205 receives the end report from the processor 206 (60
1) The information for the next data request added thereto is checked (602), and if the next input / output is possible by the drive, the drive side input / output state of the drive is made transferable (603), Thus, when the next input / output is not possible, the drive side input / output state of the drive is set to transfer disabled (607). Then, it is checked whether there is a drive that can request I / O next (604). If there is such a drive, the drive that requests I / O next is selected from the drives that can be input / output according to the I / O status management table. It is selected (605) and an input / output command is issued to the drive (606).

As described above, according to the data transfer control method of this embodiment, the control device 201 and the storage device 202
Since the control device 201 manages the data transfer state, it is possible to select a drive that can transfer data without fail for the next data transfer request, and it is possible to prevent a meaningless data transfer instruction. In addition, the control device 2
01 divides an input / output request from the higher-level device 100 into a plurality of data transfer requests and requests the storage device 202 to manage the data transfer state for each drive, thereby immediately knowing that the data transfer is disabled. Control device 20
By making a data transfer request to another storage medium capable of data transfer at 1, it is possible to perform effective multiplex data transfer control even with one data transfer path.

[0039]

As described above in detail, according to the data transfer control method of the present invention, the data transfer speeds of the host device side and the storage device (drive) side are different, or the data transfer status is changed by error recovery or the like. In the input / output device that changes, the control device manages and understands the data transfer status of both the host device side and the storage device side. Therefore, even if the above transfer status change occurs during data transfer, Prior to issuing the data transfer request, it is possible to surely know the change in the transfer status of both the upper device side and the storage device side in advance, thereby avoiding meaningless data transfer instruction and controlling This has the effect of reducing overhead.

Further, by dividing a plurality of input requests from a host device into a plurality of data requests and making the input requests in units of one or a plurality of logical blocks for a plurality of storage media, it is possible to realize a substantial transfer through a single transfer path. This has the effect of enabling simultaneous simultaneous parallel transfer and effective multi-data transfer processing.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an input / output device that is an embodiment of the present invention.

FIG. 2 is a block diagram of an information processing system including the input / output device of this embodiment.

FIG. 3 is a diagram showing a control flow and a data flow in this embodiment.

FIG. 4 is an explanatory diagram of a basic control sequence between a control device and a storage device in this embodiment.

FIG. 5 is an explanatory diagram of a multiplex control sequence between a control device and a storage device in this embodiment.

FIG. 6 is a flow chart showing a data transfer instruction issuing procedure in this embodiment.

[Explanation of symbols]

 100 Upper device 200 Input / output device 201 Control device 202 Storage device 203 Channel buffer 204-206 Control processor 207 Drive buffer 208 Disk drive 210-213 Sub-processor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiko Matsumoto 2880 Kozu, Odawara-shi, Kanagawa Stock company Hitachi Odawara factory (72) Inventor Mamoru Torochi 2880 Kunizu, Odawara, Kanagawa Hitachi Odawara Co., Ltd. Inside the factory (72) Inventor Ikuo Kawaguchi 2880 Kokuzu, Odawara, Kanagawa Hitachi Ltd. Odawara factory (72) Inventor Akira Kurano 2880 Kozu, Odawara, Kanagawa Hitachi Ltd. Odawara factory

Claims (4)

[Claims] 1. A storage device having a drive buffer for temporarily holding data and having one or more storage devices connected to one or more storage media, and a channel buffer for temporarily holding data. In a data transfer method of an input / output device having a control device for managing and a single data transfer path connecting the control device and the storage device, data transfer between the control device and the storage device In the case of performing the above, every time one or a plurality of data blocks are transferred between the channel buffer and the drive buffer, the control device informs the data transfer executability of the next data transfer in the storage medium from the storage device. By receiving the data, the data transfer states of both the upper device side and the storage device side are recognized, and the next data is received according to the recognition result. A data transfer control method characterized by being configured to perform data transfer. 2. The control device is configured to manage the received information on whether or not the data transfer can be executed, and to determine a storage medium to which the data is to be transferred next based on this information. The data transfer control method according to claim 1. 3. The control device selects a storage medium to which data can be transferred next based on the data transfer execution availability information, and when there is no data transferable storage medium, the data transfer request is canceled and data from the storage device is canceled. 3. The data transfer control system according to claim 1, wherein the data transfer is started after waiting for the transfer resumption notification. 4. The control device divides an input / output request received from a host device into a plurality of data requests, and transfers data to one or a plurality of storage media between the channel buffer and the drive buffer. 4. The data transfer control method according to claim 1, wherein the data transfer control method is configured to be performed.