Isolate I/O subsystem performance issues on Linux

Created:

2016-12-18 06:53:29 UTC

Modified:

2017-08-08 13:37:34 UTC

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Isolate I/O subsystem performance issues on Linux

Applicable to:

  • Plesk for Linux

Symptoms

How to isolate I/O subsystem performance issues.

Resolution

  1. Install and run bonnie++ to measure disk and file system performance

    # yum install bonnie++ 
    # bonnie++ -d /tmp -r 2048 -u root -n 100|bon_csv2txt
  2. Analyze it output. In the example below you can see that there is a huge latency on I/O operations

    Version      1.96   ------Sequential Output------ --Sequential Input- --Random-
    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
    Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
    domain.tld 4G 494 78 10522 1 7742 0 3091 99 5507963 99 9801 36
    Latency 19978us 20748ms 71339ms 4671us 506us 14475us
    ------Sequential Create------ --------Random Create--------
    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
    files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
    domain.tld 100 166 0 +++++ +++ 3782 5 776 1 +++++ +++ 3852 5
    Latency 2769ms 636us 791us 6815ms 232us 617us
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