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Test disk speed

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You'll need to check the speed of your disks when you carry out your tests. Whether you want to compare the performance of different disks or just check if they are satisfactory.

 

Requirements

  • A Public Cloud Instance in your OVHcloud account
  • Administrative (sudo) access to your instance via SSH (Linux) or RDP (Windows)

 

Instructions

Install the test command

On Linux
On Windows

The command that you need to test your disk speed is called fio, and is not installed on your server by default.

To install fio, run the following command:

apt install fio

 

Test your disk speed

On Linux
On Windows

To test your disk speed, run the following command:

Info

Please note that you will need to modify the --numjobs argument to reflect the number of CPUs that your instance has.

You can retrieve a list of arguments and their functions directly from the fio guide.

fio --name=rand-write --ioengine=libaio --iodepth=32 --rw=randwrite --invalidate=1 --bsrange=4k:4k,4k:4k --size=512m --runtime=120 --time_based --do_verify=1 --direct=1 --group_reporting --numjobs=1

 

Analyze the data

On Linux
On Windows

Once the test is finished, you will get a result similar to the following:

fio-3.37
Starting 1 process
Jobs: 1 (f=1): [w(1)][100.0%][w=156MiB/s][w=40.0k IOPS][eta 00m:00s]
rand-write: (groupid=0, jobs=1): err= 0: pid=2974: Sat Nov 16 03:21:07 2024
  write: IOPS=40.0k, BW=156MiB/s (164MB/s)(18.3GiB/120001msec); 0 zone resets
    slat (usec): min=2, max=812, avg= 4.65, stdev= 1.89
    clat (usec): min=53, max=12487, avg=794.13, stdev=75.55
     lat (usec): min=58, max=12492, avg=798.78, stdev=75.53
    clat percentiles (usec):
     |  1.00th=[  742],  5.00th=[  775], 10.00th=[  783], 20.00th=[  783],
     | 30.00th=[  791], 40.00th=[  791], 50.00th=[  799], 60.00th=[  799],
     | 70.00th=[  799], 80.00th=[  807], 90.00th=[  807], 95.00th=[  816],
     | 99.00th=[  840], 99.50th=[  857], 99.90th=[ 1037], 99.95th=[ 1434],
     | 99.99th=[ 4883]
   bw (  KiB/s): min=159904, max=191976, per=100.00%, avg=160265.41, stdev=2060.10, samples=239
   iops        : min=39976, max=47994, avg=40066.36, stdev=515.02, samples=239
  lat (usec)   : 100=0.01%, 250=0.07%, 500=0.30%, 750=0.94%, 1000=98.56%
  lat (msec)   : 2=0.10%, 4=0.01%, 10=0.01%, 20=0.01%
  cpu          : usr=7.37%, sys=20.48%, ctx=4614084, majf=0, minf=10
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,4803938,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=32

Run status group 0 (all jobs):
  WRITE: bw=156MiB/s (164MB/s), 156MiB/s-156MiB/s (164MB/s-164MB/s), io=18.3GiB (19.7GB), run=120001-120001msec

Disk stats (read/write):
  sda: ios=0/4799786, merge=0/29, ticks=0/3797382, in_queue=3797385, util=74.39%

The line we are interested in is the fifth, which contains the IOPS:

write: IOPS=40.0k, BW=156MiB/s (164MB/s)(18.3GiB/120001msec); 0 zone resets

We can see that the performance of the main disk is around 40.0k IOPS.

 

Additional disk

On Linux
On Windows

To test the speed of an additional disk, you will need to mount the disk with the following command:

cd /mnt/disk

 

Analyze the data:

The IOPS value will depend on the type of additional disk you use. In the example below, we ran the test on a High speed volume:

fio-3.37
Starting 1 process
Jobs: 1 (f=1): [w(1)][100.0%][w=11.9MiB/s][w=3054 IOPS][eta 00m:00s]
rand-write: (groupid=0, jobs=1): err= 0: pid=2946: Sat Nov 16 03:13:20 2024
  write: IOPS=3052, BW=11.9MiB/s (12.5MB/s)(1431MiB/120011msec); 0 zone resets
    slat (usec): min=2, max=8119, avg= 6.14, stdev=53.35
    clat (usec): min=114, max=20721, avg=10477.33, stdev=587.51
     lat (usec): min=117, max=20724, avg=10483.47, stdev=584.33
    clat percentiles (usec):
     |  1.00th=[ 9634],  5.00th=[10028], 10.00th=[10028], 20.00th=[10159],
     | 30.00th=[10159], 40.00th=[10290], 50.00th=[10290], 60.00th=[10421],
     | 70.00th=[10552], 80.00th=[11076], 90.00th=[11207], 95.00th=[11338],
     | 99.00th=[11469], 99.50th=[11469], 99.90th=[12780], 99.95th=[14877],
     | 99.99th=[17433]
   bw (  KiB/s): min=12160, max=14648, per=100.00%, avg=12217.46, stdev=158.45, samples=239
   iops        : min= 3040, max= 3662, avg=3054.36, stdev=39.61, samples=239
  lat (usec)   : 250=0.01%, 500=0.04%, 750=0.03%, 1000=0.01%
  lat (msec)   : 2=0.01%, 4=0.01%, 10=5.06%, 20=94.84%, 50=0.01%
  cpu          : usr=0.70%, sys=1.82%, ctx=143740, majf=0, minf=10
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,366290,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=32

Run status group 0 (all jobs):
  WRITE: bw=11.9MiB/s (12.5MB/s), 11.9MiB/s-11.9MiB/s (12.5MB/s-12.5MB/s), io=1431MiB (1500MB), run=120011-120011msec

Disk stats (read/write):
  sdb: ios=0/365996, merge=0/23, ticks=0/3826413, in_queue=3826472, util=96.45%
write: IOPS=3052, BW=11.9MiB/s (12.5MB/s)(1431MiB/120011msec); 0 zone resets

We can see that the performance of the additional disk is around 3052 IOPS.

 

Go further

Browse all the Block Storage guides.

Browse the rest of the OVHcloud US documentation for guides on our other products and services.

Learn more about Block Storage on the OVHcloud US website.