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 make full use of the performance of the multi-core and 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 later 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, the device name of the ESSD is /dev/your_device. Replace it with your actual device name. For more information, see ESSDs.
Operation notes
Warning
- You can obtain accurate test results by testing raw disk partitions. However, you may destroy the file system structure in a raw disk partition if you directly test the partition. Before you test a raw disk, we recommend that you back up your data by taking a snapshot of the disk. For more information, see Create a snapshot of a disk.
- We recommend that you do not test a disk in which the operating system is located or a disk that stores important data. To prevent data loss, we recommend that you use a new Elastic Compute Service (ECS) instance that does not contain data for the test.
Procedure
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
Note In 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 runsjobs
to bind queues to different CPU cores. These queues have different queue IDs. 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 your 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 your 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.
- Run the