This topic describes how to test the IOPS performance of an enhanced SSD (ESSD). The specifications of the disk and the test conditions affect the test results. If you configure the test conditions as described in the following example to maximize the performance of a multi-core, high-concurrency system, you can obtain an IOPS value of one million when you perform a stress test on the ESSD.
Test conditions
Sample operation: random write (randwrite).
Image: We recommend that you use a more recent version of a Linux public image provided by Alibaba Cloud, such as CentOS 7.4 64-bit, CentOS 7.3 64-bit, CentOS 7.2 64-bit, or Alibaba Cloud Linux 2.1903 64-bit.
Tool: We recommend that you use FIO.
Instance type: We recommend that you use ecs.g7se.32xlarge. For more information, see g7se, storage-enhanced general-purpose instance family.
ESSD: We recommend that you use an ESSD at performance level 3 (PL3 ESSD). In this example, /dev/your_device is used as the device name of an ESSD. Replace it with the actual device name. For more information, see ESSDs.
Precautions
You can obtain accurate test results by testing raw disks. However, you may destroy the file system structure in a raw disk if you directly test the disk. Before you test a raw disk, we recommend that you back up your data by creating a snapshot for the disk. For more information, see Create a snapshot for a disk.
We recommend that you do not test a disk on which the operating system resides or a disk that stores important data. To prevent data loss, we recommend that you use a new Elastic Compute Service (ECS) instance that contains no data for the test.
Procedure
- Connect to an ECS instance. For more information, see Connect to an instance by using VNC.
Run the following commands in sequence to install libaio and FIO:
sudo yum install libaio -y sudo yum install libaio-devel -y sudo yum install fio -y
Run the following command to switch the path:
cd /tmp
Run the following command to create the test100w.sh script:
vim test100w.sh
Paste the following content to the test100w.sh script.
For information about the script content, see the Details about the test100w.sh script section of this topic.
function RunFio { numjobs=$1 # The number of test threads. In this example, the value is 10. iodepth=$2 # The maximum number of concurrent I/O requests. In this example, the value is 64. bs=$3 # The data block size per I/O. In this example, the value is 4k. rw=$4 # The read and write policy. In this example, the value is randwrite. size=$5 filename=$6 # The name of the test file. In this example, the value is /dev/your_device. nr_cpus=`cat /proc/cpuinfo |grep "processor" |wc -l` if [ $nr_cpus -lt $numjobs ];then echo "Numjobs is more than cpu cores, exit!" exit -1 fi let nu=$numjobs+1 cpulist="" for ((i=1;i<10;i++)) do list=`cat /sys/block/your_device/mq/*/cpu_list | awk '{if(i<=NF) print $i;}' i="$i" | tr -d ',' | tr '\n' ','` if [ -z $list ];then break fi cpulist=${cpulist}${list} done spincpu=`echo $cpulist | cut -d ',' -f 2-${nu}` echo $spincpu fio --ioengine=libaio --runtime=30s --numjobs=${numjobs} --iodepth=${iodepth} --bs=${bs} --size=${size} --rw=${rw} --filename=${filename} --time_based=1 --direct=1 --name=test --group_reporting --cpus_allowed=$spincpu --cpus_allowed_policy=split } echo 2 > /sys/block/your_device/queue/rq_affinity sleep 5 RunFio 10 128 4k randwrite 1024g /dev/your_device
Modify the parameters in the test100w.sh script based on the actual conditions.
Replace
your_device
with the actual device name of the ESSD. Example: nvme1n1.Replace 10, 64, 4k, randwrite, and /dev/your_device in
RunFio 10 64 4k randwrite /dev/your_device
with the actual values.If data loss of the ESSD does not affect your business, you can set
filename
to a device name. Example: filename=/dev/vdb. Otherwise, setfilename
to a file directory. Example: filename=/mnt/test.image.
WarningYou can obtain accurate test results by testing raw disks. However, you may destroy the file system structure in a raw disk if you directly test the disk. Before you test a raw disk, we recommend that you back up your data by creating a snapshot for the disk. For more information, see Create a snapshot for a disk.
We recommend that you do not test a disk on which the operating system resides or a disk that stores important data. To prevent data loss, we recommend that you use a new Elastic Compute Service (ECS) instance that contains no data for the test.
Run the following command to test the performance of the ESSD:
sh test100w.sh
If the
IOPS=***
result is displayed in the command output, the performance stress test for the ESSD is complete.
Details about the test100w.sh script
In the script, the following command sets the
rq_affinity
parameter to 2:echo 2 > /sys/block/your_device/queue/rq_affinity
Value of rq_affinity
Description
1
Indicates that the block device delivers received I/O completion events to the group of the vCPUs that submit the corresponding I/O requests. In scenarios where multiple threads run concurrently, I/O completion events may be delivered only to one vCPU and cause a performance bottleneck.
2
Indicates that the block device delivers received I/O completion events to the vCPUs that submit the corresponding I/O requests. In scenarios where multiple threads run concurrently, each vCPU can deliver its maximum performance.
The following command runs
jobs
to bind queues to different CPU cores:fio -ioengine=libaio -runtime=30s -numjobs=${numjobs} -iodepth=${iodepth} -bs=${bs} -rw=${rw} -filename=${filename} -time_based=1 -direct=1 -name=test -group_reporting -cpus_allowed=$spincpu -cpus_allowed_policy=split
NoteIn normal mode, a device has a single request queue. This request queue becomes a performance bottleneck when multiple threads concurrently process I/O requests. In multi-queue mode, a device can have multiple request queues to process I/O requests and deliver the maximum backend storage performance. For example, assume that you have four I/O threads. To make full use of multi-queue mode and improve storage performance, you must bind these threads to the CPU cores that correspond to different request queues.
Parameter
Description
Example
numjobs
The number of I/O threads.
10
/dev/your_device
The device name of the ESSD.
/dev/nvme1n1
cpus_allowed_policy
The parameter provided by FIO to bind vCPUs. FIO provides the
cpus_allowed_policy
andcpus_allowed
parameters to bind vCPUs.split
The preceding command runs
jobs
to bind queues with different queue IDs to different CPU cores. To view the ID of the CPU core to which a queue is bound, perform the following steps:Run the
ls /sys/block/your_device/mq/
command. In this command, replaceyour_device
with the actual device name. Example: nvme1n1. This command returns the ID of the queue for an ESSD whose device name is in the /dev/vd* format.Run the
cat /sys/block/your_device/mq//cpu_list
command. In this command, replaceyour_device
with the actual device name. Example: nvme1n1. This command returns the ID of the CPU core to which the queue for an ESSD is bound. The device name of the ESSD is in the /dev/vd* format.