JP2001344073A - Disk input and output schedule device and method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly precise scheduling by highly precisely predicting an input and output processing time even when a disk device under the control of a disk input and output schedule device are constituted of plural disk drives. SOLUTION: In this disk input and output schedule method, input and output requests to a disk device are divided into plural groups according to the classifications of the input and output requests, and a time when the disk device is continuously used is assigned to each group, and disk constitution to be used is read from the disk device corresponding to the input and output requests, and the processing time is predicted according to the read disk constitution, and the same queue is continuously read until the total of the continuous predicted values exceeds the time assigned to the queue which is being read at present, and when the total of the continuous predicted values exceeds the assigned time, the queues to be read are successively switched.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention classifies input / output requests to a disk device for each type of input / output request,
The present invention relates to a disk input / output scheduling device that uses a disk in a time-sharing manner between groups.

In a storage system that manages data using a disk device such as a hard disk drive, a plurality of types of input / output, for example, OLTP operations (On L
As in ineTransaction Processing), it is necessary to perform input / output of a random access system that requires a guaranteed response time, and input / output of a sequential access system in which the amount of processing per unit time is important, such as a database backup operation.

[0003] In particular, in a mission critical OLTP business such as a window business, input / output performance requirements include:
It is required to guarantee a maximum response time in addition to the average response time.

However, since the optimal scheduling method is different for input / output requests of different types, the time zones are usually divided so that the operations of the random access system and the operations of the sequential access system do not compete with each other, and the time periods are adjusted accordingly. The scheduling method is switched and operated.

For example, in the daytime, since the OLTP operation is performed, the processing amount per unit time is reduced. However, a scheduling method for guaranteeing the response time is adopted, and the database backup operation is performed at night after the operation is completed. ,
Although the response time cannot be guaranteed, a scheduling method that emphasizes the amount of processing per unit time is adopted.

However, with an increase in demand for non-stop work, it is necessary to continue the OLTP work even at night, and it is necessary to execute the OLTP work and the database backup work in the same time zone.

[0007]

2. Description of the Related Art FIG. 5 shows a configuration example of a conventional disk input / output scheduling device.

In the conventional example, the type of an input / output request is determined and divided into input / output groups such as a random access and a serial access. Quantum ".

When the disk I / O schedule device receives an I / O request, it determines the type of the I / O request, divides the I / O request into each I / O group, and stores the I / O request in a queue indicating the processing order of each. I do.

When processing an I / O request, the I / O request processing means refers to the queue designated by the I / O schedule means, and sends the referenced I / O request to the I / O schedule means and the disk device. The input / output schedule means continuously designates the same queue until the quantum assigned to the queue is used up, and switches the designated queue when the assigned quantum is used up.
As a result, the disk devices are used in a time sharing manner between the input / output groups.

A processing flow in the case of scheduling input / output requests in two input / output groups of random access and serial access will be described with reference to FIG.

In the initial state, as shown in FIG. 7A, a random access group is assigned a quantum of τ1 = 120 ms, and a serial access group is assigned a quantum of τ2 = 60 ms.

The input / output request is sent to the input / output type discriminating means 55 via the input / output request receiving means 54 of the disk input / output schedule device 53. The input / output type determining means 55 determines whether the received input / output request is a random access or a serial access, and stores the random access request in the queue 1 and the serial access request in the queue 2 as shown in FIG. I do.

When processing an I / O request, the I / O request processing means 58 first refers to the queue 1, extracts the I / O request RQ11 from the queue 1, and sends the I / O request to the I / O schedule means 57 and the disk device 51. Send to (S
61).

The input / output schedule means 57 analyzes the input / output request, determines the size of the data, and determines whether the data is read or written, and calculates a predicted processing time τrq. Next, τrq is subtracted from the remaining quantum Δτ (in the initial state, the assigned quantum τ1) to obtain the remaining quantum Δτ (S62). Next, the remaining quantum Δ
The sign of τ is determined (S63), and if Δτ is positive or 0, the process returns to S61, where the next input / output request is taken out of the queue currently being referred to, and the same processing is performed. I / O request RQ
The state of the quantum after processing to 1n is shown in FIG. 7-c).

In FIG. 7C, the current quantum is 120 ms assigned to the I / O group 1, and the time used in the processing of RQ11 to RQ1n is 1
Since it is 16 ms, the remaining quantum Δτ = 4 ms.

In the processing of the next input / output request RQ1n + 1, 8
When using ms, the remaining quantum Δτ = -4 ms, and the process proceeds from S63 to S64 to switch the queue instructing the input / output request processing means to the queue 2.

In this way, scheduling is performed when accesses of different types, such as random access and sequential access, are received in the same time zone.

[0019]

However, if the disk device under the control of the disk input / output schedule device is not a single disk drive but is composed of a plurality of disk drives such as RAID 5, for example, The error in the prediction time increases.

FIG. 8 shows a situation when data is input / output to / from a disk drive. In a disk drive, a unit for inputting and outputting data on a disk medium, that is, a strip is determined, and data is input and output in strip units. Here, the processing when the strip size is 60 KB will be described.

When there is an input / output request with a data size of 30 KB and data is stored from the beginning of the strip (a), the data enters one strip and accesses one disk, but (b) If stored from the 40th KB of the strip, the data is split into two strips. In this case, the second strip is 1
Access to a two-disk drive may be required because it is not necessarily on the same disk drive as the first strip.

The input / output processing time increases each time a disk drive to be accessed is added. Therefore, even with an input / output request of the same data size, one input / output request may actually become an input / output request to a plurality of disk drives depending on the position where data is stored, and the processing time may increase.

Therefore, when the disk device is composed of a plurality of disk drives, the conventional disk input / output scheduling device has a large error in the predicted input / output processing time.

An object of the present invention is to accurately predict an input / output processing time even when a disk device under the control of the disk input / output scheduling device is composed of a plurality of disk drives, and to perform highly accurate scheduling. Is to do.

[0025]

SUMMARY OF THE INVENTION The present invention provides an input / output type discriminating means for dividing input / output requests to a disk device into a plurality of groups according to the type of the input / output requests, and an input / output request assigned to each group. Queue control means for storing the input / output request in a queue for displaying the processing order of the data, and read the input / output request from the queue in accordance with the instruction of the allocation time control means, and issue the input / output request to the disk device and the processing time prediction means. An input / output request processing unit, a configuration determining unit for reading and determining a disk configuration to be used in response to the input / output request from the disk device, and a predicted value of a processing time of the input / output request according to the determination result of the configuration determining unit And a time for continuously using the disk device for each of the queues, and the total of the continuous predicted values is currently being read out. Instruct the I / O request processing means to read the same queue continuously until the time allotted to the queue exceeds the time assigned to the queue. Switching time control means.

In the disk input / output schedule apparatus according to the present invention, the input / output request receiving means receives the input / output request and sends it to the input / output type determining means. The input / output type determining unit determines the type of the received input / output request, divides the input / output request into groups for each type of input / output request, and stores them in a queue corresponding to each group.

When processing an input / output request, the input / output request processing unit refers to the queue specified by the allocation time control unit and sends the input / output request to the processing time prediction unit and the disk device.

The configuration determining means reads the disk configuration to be used in response to the input / output request from the disk device, determines the disk configuration to be used in the input / output request, and sends it to the processing time estimating means.

The processing time estimating means having received the disk configuration obtains the processing estimated time from the processing estimated time of the unit of the input / output request and the disk configuration, and sends it to the allocated time controlling means.

As a specific process, for example, the number of disk drives for processing each input / output request and the number of strips, which is a unit of input / output processing, are determined from the disk configuration, and each disk drive corresponding to the input / output request is determined. Is calculated, and the sum is defined as the predicted processing time.

The allocated time control means subtracts the estimated processing time from the quantum allocated to the queue, and continuously designates the same queue until the remaining quantum becomes zero. By switching the queue instructed to the processing means, scheduling based on the disk configuration is performed.

According to a second aspect of the present invention, there is provided the disk input / output scheduling apparatus according to the first aspect, wherein the processing time prediction means determines whether the input / output request is a read or a write.
It is characterized in that prediction of the read processing time and prediction of the write processing time are individually performed.

According to a third aspect of the present invention, there is provided the disk input / output scheduler according to the first aspect, wherein the configuration determining means determines a disk drive configuration and a strip configuration to be used in response to the input / output request. It is characterized by doing.

According to a fourth aspect of the present invention, there is provided the disk input / output scheduler according to the first aspect, wherein the allocation time control means stores the result of the processed input / output request for each group. The present invention is characterized in that it comprises a request result accumulating means and a quantum length control means for determining a time for each group to use the disk device continuously according to the result of the input / output request.

[0035]

FIG. 1 shows a configuration example of the present invention.
Hereinafter, a case where the disk device under the control of the disk input / output scheduling device of the present invention has a RAID5 configuration will be described with reference to the following conditions as an example in comparison with the conventional example. 1. Input / output request group: input / output request group 1 = random access input / output request, input / output request group 2 = serial access input / output request. 2. Quantum size in initial state: Quantum τ1 of group 1 = 120 ms × 5 = 600 ms, group 2
Quantum τ2 = 60 ms × 5 = 300 ms 3.1 predicted read processing time τr = 4 ms, and one predicted write processing time τw = 5 ms.

FIG. 2 shows the flow of the input / output request processing in this case.
FIG. 3 shows the states of the quantum and the queue in each process.

In the initial state, each input / output group is
The quantum shown in -a) is assigned.

The input / output request accepting means 4 includes the input / output request unit 2
Is sent to the input / output type determining means 5. The input / output type determining means 5 determines whether the type of the received input / output request is random access or serial access, and stores them in the queue 1 and the queue 2 of the queue control means 6 (FIG. 3B).

The processing of an input / output request will be described with reference to the processing flow example of FIG. The input / output request processing means 8 refers to the queue designated by the allocation time control means 10, extracts the input / output request from the queue, and converts the input / output request into the processing time prediction means 7.
And the disk device 1 (S21).

The processing time predicting means 7 determines whether the input / output request is a read request or a write request (S22). If the input / output request is a read, the processing predicted time τp = τr = 4 ms (S23), and when the input / output request is a write, τp = τw = 5ms (S24).

The configuration determining means reads from the disk device the disk configuration to be used in response to the input / output request, for example, the disk drive and strip to be accessed (S25).

The processing time predicting means 7 obtains a processing predicted time τrq from τp and the disk configuration (S26).

The allocated time control means 10 calculates the remaining quantum Δτ (in the initial state, the allocated quantum τ
Τrq is subtracted from 1) to calculate the remaining quantum Δτ (S27).

Next, the sign of the remaining quantum .DELTA..tau. Is determined (S28). If .DELTA..tau. Is positive or 0, the process returns to S21. If .DELTA..tau. Is negative, a queue for instructing the input / output request processing means is stored in the queue 2. Switching (S29), the process returns to S21.

FIG. 4C shows an example of the state after processing up to the input / output request RQ1n. In FIG. 4-c), the current quantum is 60 assigned to the I / O group 1.
At 0 ms, the time consumed by RQ11 to RQ1n is 5
Since it is 96 ms, the remaining quantum Δτ = 4 ms.

Next, the extracted input / output request RQ1n + 1
Is a read request and enters one strip as shown in FIG. 10-a), for example, the number of disk drives = 1 and the number of strips = 1 become a disk configuration, and τrq = 4 m
s, the remaining quantum Δτ = 4 ms−4 ms = 0 ms, and the process returns to S21.

When the input / output request is divided into two strips as shown in FIG. 8B and the two strips become different disk drives, for example, the number of disk drives = 2, the number of strips = 2 Τ
rq = 8 ms, remaining quantum Δτ = 4 ms−8 ms
= −4 ms, and the queue instructed to the input / output request processing means 8 is switched from the queue 1 to the queue 2 (S29).
Return to 21.

When the input / output request is not stored in the queue 2, the queue to be instructed is switched to the queue 1 again.

As another embodiment, an input / output request result accumulating means 11 and a quantum length control means 12 are added to the allocated time control means 10, and the quantum is redistributed according to the result of the input / output request.

For example, as shown in FIG. 4, the quantum distribution τ1: τ2 = 600ms: 300m set in the initial state.
s, the accumulated result of the input / output request is τ1: τ2 =
When the bias is 604 ms: 200 ms, the quantum is redistributed to τ1: τ2 = 604 ms: 200 ms, and the subsequent scheduling is performed.

Note that the quantum redistribution value is fixed to the maximum value, for example, τ1: τ
2 = 600 ms: 200 ms.

[0052]

As described above, according to the present invention,
Even if a disk device under the control of the disk input / output schedule device is configured by a plurality of disk drives, The processing time is estimated based on the disk configuration on which the input / output is executed. 2. The processing time is predicted individually for the read processing and the write processing. As a result, highly accurate input / output processing time is predicted, and highly accurate scheduling is performed.

Further, by accumulating the results of input / output requests and redistributing the quantum based on the results, more accurate scheduling is performed.

[Brief description of the drawings]

FIG. 1 is a configuration example of the present invention.

FIG. 2 is an example of a processing flow of an input / output request according to the present invention.

FIG. 3 shows the quantum and cue states according to the present invention.

Fig. 4 I / O processing results for each I / O group

FIG. 5 is a schematic configuration of a conventional example.

FIG. 6 is a processing flow of a conventional disk input / output scheduling device.

FIG. 7: Quantum and cue state of conventional example

FIG. 8 is a processing example of an input / output request

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disk device 2 I / O request part 3 Disk I / O schedule device 4 I / O request accepting means 5 I / O type discriminating means 6 Queue control means 7 Processing time prediction means 8 I / O request processing means 9 Configuration discriminating means 10 Allocation time control means 11 I / O request result accumulation means 12 Quantum length control means

Claims (7)

[Claims] An input / output type determining means for dividing input / output requests to a disk device into a plurality of groups according to the type of the input / output requests, and a queue for displaying a processing order of the input / output requests assigned to each group. Queue control means for storing input / output requests, input / output request processing means for reading input / output requests from the queue in accordance with instructions from the allocation time control means, and issuing input / output requests to the disk device and processing time prediction means; Configuration determining means for reading and determining a disk configuration to be used in response to the input / output request from the device; processing time predicting means for calculating a predicted value of a processing time of the input / output request according to the determination result of the configuration determining means; A time period for continuously using the disk device is assigned to each of the queues, and a total of the continuous predicted values is assigned to the queue currently being read out. Continuously until more than between,
And an assignment time control means for instructing the input / output request processing means to read the same queue and sequentially switching the queue instructed to the input / output request processing means when the allocated time is exceeded. Disk I / O scheduling device. 2. The disk input / output scheduling apparatus according to claim 1, wherein the processing time predicting unit determines whether the input / output request is a read or a write, and estimates a read processing time and a write processing time. And a disk input / output schedule device. 3. The disk input / output scheduling apparatus according to claim 1, wherein the configuration determining unit determines a disk drive configuration and a strip configuration to be used in response to the input / output request. I / O scheduling device. 4. The disk input / output scheduling apparatus according to claim 1, wherein the allocation time control means includes: an input / output request result storage means for storing the processed input / output request results for each group; A disk input / output scheduler comprising: quantum length control means for determining a time for each group to continuously use a disk device in accordance with an output request result. 5. An input / output type determining procedure for dividing input / output requests to a disk device into a plurality of groups according to the type of the input / output requests, and a queue for displaying a processing order of the input / output requests assigned to each group. A queue control procedure for storing the input / output request, an input / output request processing procedure for reading the input / output request from the queue in accordance with the instructions of the allocation time control procedure, and issuing the input / output request to the disk device and the processing time prediction procedure; A configuration determination procedure for reading and determining a disk configuration to be used in response to an I / O request from a disk device; a processing time prediction procedure for calculating a predicted value of a processing time of the I / O request in accordance with a determination result of the configuration determination procedure; A time period for continuously using the disk device is assigned to each queue, and a total of the continuous predicted values is assigned to the queue currently being read. Continuously until more than,
An assignment time control procedure for instructing the input / output request processing procedure to read the same queue and sequentially switching queues instructed to the input / output request processing procedure when the allocated time is exceeded. A computer-readable recording medium on which a program is recorded. 6. An input / output request to a disk device is divided into a plurality of groups according to the type of the input / output request, and the input / output request is stored in a queue for displaying a processing order of the input / output request assigned to each group. When allocating the time for continuously using the disk device for each queue, and processing the input / output request, read the input / output request from the queue and issue the input / output request to the disk device and the processing time estimating means. Then, a disk configuration to be used in response to the input / output request is read from the disk device. The same queue is continuously read until the sum of the continuous predicted values exceeds the time allotted to the queue currently being read. Total Hakachi is, if it exceeds the time allotted, the disk input-output scheduling method and performing scheduling for switching the queue to be read sequentially. 7. An input / output type determining procedure for dividing input / output requests to a disk device into a plurality of groups according to the type of the input / output requests, and a queue for displaying a processing order of the input / output requests assigned to each group. A queue control procedure for storing the input / output request, an input / output request processing procedure for reading the input / output request from the queue in accordance with the instructions of the allocation time control procedure, and issuing the input / output request to the disk device and the processing time prediction procedure; A configuration determination procedure for reading and determining a disk configuration to be used in response to an I / O request from a disk device; a processing time prediction procedure for calculating a predicted value of a processing time of the I / O request in accordance with a determination result of the configuration determination procedure; A time period for continuously using the disk device is assigned to each queue, and a total of the continuous predicted values is assigned to the queue currently being read. Continuously until more than,
A program for instructing an input / output request processing procedure to read the same queue and executing an allocation time control procedure for sequentially switching queues instructed by the input / output request processing procedure when the allocated time is exceeded.