Test the IOPS performance of an enhanced SSD

Procedure

1. Remotely connect to an ECS instance. For more information, see Connect to a Linux instance by using VNC.
2. Run the following commands in sequence to install the libaio and fio tools:

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

3. Switch the directory.

   cd /tmp

4. Create the test100w.sh script.

   vim test100w.sh

5. Paste the following snippet of code to the test100w.sh script:

   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 size of the data block per I/O. In this example, the value is 4k.
    rw=$4        # The read and write policy. In this example, the value is randwrite.
    filename=$5  # The name of the file to be tested. In this example, the value is /dev/vdb.
    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/vdb/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} --rw=${rw} --filename=${filename} --time_based=1 --direct=1 --name=test --group_reporting --cpus_allowed=$spincpu --cpus_allowed_policy=split
   }
   echo 2 > /sys/block/vdb/queue/rq_affinity
   sleep 5
   RunFio 10 64 4k randwrite /dev/vdb

6. Modify the parameter settings in the test100w.sh script based on your actual environment.
   • Modify vdb based on the actual device name of the ESSD.
   • Modify 10, 64, 4k, randwrite, and /dev/vdb in RunFio 10 64 4k randwrite /dev/vdb.
   • If you want to proceed with this operation, set filename to a device name such as [/dev/vdb]. If you do not want to risk data loss, set filename to a file path such as [/mnt/test.image].
7. Test the performance of the ESSD.

   sh test100w.sh

   If the IOPS=*** result appears, the performance stress test for the ESSD is complete.

Details of the test100w.sh script

• In the script, the following command sets the rq_affinity parameter to 2:

  echo 2 > /sys/block/vdb/queue/rq_affinity

  Value of rq_affinity	Description
  1	Indicates that the block device delivers the received I/O completion events to the group of 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 the received I/O completion events to the vCPU that submits 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 run concurrently to process I/O. In multi-queue mode, a device can have multiple request queues to process I/O and deliver the maximum backend storage performance. Assume that you have four I/O threads. To make full use of the 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/vdb	The device name of the ESSD.	/dev/vdb
  cpus_allowed_policy	The cpus_allowed_policy and cpus_allowed parameters provided by fio to bind vCPUs.	split

  The preceding command runs jobs to bind queues to 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/vd*/mq/ command to view the ID of the queue for an ESSD whose device name is in the /dev/vd* format.
  • Run the cat /sys/block/vd*/mq//cpu_list command to view the ID of the CPU core to which the queue returned in the previous step is bound.