This practice describes how to use the FIO tool to test the performance of EVS.

Overview of Practices

EVS has different performance and prices depending on EVS type. For more information, see Disk Type and Performance Description.

The FIO tool is commonly used for stress testing and performance verification of disks. This practice uses the FIO tool to introduce the method to test the performance of EVS.

Preparations Before Operation

This section describes the preparations you must make before you begin operations, including inspection before testing, installing the tools, and describing FIO parameters.

Inspection before Testing

Before testing, mount and initialize the EVS. For more information, see Mounting EVS and Initializing EVS.

Note:

When testing disk performance, we recommend that you directly test the raw data disk (for example, /dev/vdb). However, the file system structure on the disk may be damaged. Therefore, back up data before testing.
We strongly recommend that you do not use system disks or data disks that contain important data as test objects. We recommend that you test the performance on a data disk that contains no data to avoid data loss.

Log in to the cloud server under test and run the following command to check whether the disk partition to test is aligned to 4KiB.

sudo fdisk -lu

If the Start value of the disk to test in the return result is divisible by 8, the disk partition is aligned to 4KiB. The returned information in the following figure indicates that the disk partition is aligned to 4KiB.

If the Start value is not divisible by 8, the disk partition is not aligned to 4KiB. In this case, delete the original partition and continue the test. Select the start cylinder number according to the 4KiB alignment.

Installing the Tools

Run the following commands in turns to install libaio and test tool FIO.

sudo yum install libaio -y
sudo yum install libaio-devel -y
sudo yum install fio –y

Introduction to FIO Parameters

Test formulas in different scenarios are basically the same. Some parameters may vary depending on test objects, as shown in the following table.

Parameter	Description
direct	Specifies the direct mode. The default value is 1. · If the value is 1, direct I/O is used, I/O cache is ignored, and data is written directly. · If the value is 0, direct I/O is not used.
numjobs	Specifies the number of concurrent threads. The default value is 1. If the disk under test performs well, we recommend that you increase the numjobs number to increase stress.
iodepth	Specifies the IP queue depth during test. Queue depth refers to the queue depth per thread, and if there are multiple thread tests, it means that each thread is the queue depth defined here. Total number of concurrent I/O of FIO =iodepth x numjobs.
rw	Specifies the read-write policy during test.Options include: ·randwrite: : random write · randread : random read · read : sequential read · write : sequential write · randrw : Hybrid random read and write
ioengine	Specifies the I/O engine selected by FIO during test. libaio is selected in this practice.
bs	Specifies the block size of each request.The default value is 4k.
size	Specifies the size of the test file. Value: · A number with a unit indicates the read/write data amount, for example, size=10G, indicating a 10-GiB read/write data amount. · A percentage indicates the ratio of read/write data amount to the total size of files, for example size=20%, indicating the read/write data amount takes 20% of the total file space.
runtime	Specifies the test time, that is, the runtime of the FIO. If this parameter is not specified, the test ends until the specified data amount is processed by the block size defined using parameter size.
time_based	Specifies the time mode used. You do not need to set this parameter value as long as the FIO tool runs based on time.
group_reporting	The statistics of the entire group are printed when multiple jobs are concurrent.
filename	Specifies the test object. It can be disk device name, for example,/dev/vdb, or file address, for example,/opt/fiotest/fiotest.txt.
name	Specifies the name of this test job.

Operation Steps

The following shows commonly-seen commands for EVS performance testing:

Description

In the following commands, the device name specified by the filename parameter is /dev/test_device. Replace it with the disk device name,for example, /dev/vdb, or file address, for example, /opt/fiotest/fiotest.txt, as required.

• Random write IOPS of the EVS under test:

fio -direct=1 -iodepth=32 -rw=randwrite -ioengine=libaio -bs=4k -size=1G -numjobs=4 -runtime=1000 -group_reporting -filename=/dev/test_device -name=RandWrite_Testing

• Random read IOPS of the EVS under test:

fio -direct=1 -iodepth=32 -rw=randread -ioengine=libaio -bs=4k -size=1G -numjobs=4 -runtime=1000 -group_reporting -filename=/dev/test_device -name=RandRead_Testing

• Sequential write throughput of the EVS under test:

fio -direct=1 -iodepth=64 -rw=write -ioengine=libaio -bs=1024k -size=1G -numjobs=1 -runtime=1000 -group_reporting -filename=/dev/test_device -name=Write_Testing

• Random write latency of the EVS under test:

fio -direct=1 -iodepth=1 -rw=randwrite -ioengine=libaio -bs=4k -size=1G -numjobs=1 -group_reporting -filename=/dev/test_device -name=RandWrite_Latency_Testing

• Random read latency of the EVS under test:

fio -direct=1 -iodepth=1 -rw=randread -ioengine=libaio -bs=4k -size=1G -numjobs=1 -group_reporting -filename=/dev/test_device -name=RandRead_Latency_Testing

Elastic Volume Service

How to Test the Performance of EVS