Automatic swap cleaning

By default, Artica try to clean the swap when it exceed 20% of the total swap defined in the system.
This rule is created by default because when the system turn to swap it increase I/O and decrease performances.
The swap system is not cleaned, this means if your server will use infinitively the swap until it is rebooted.
The Artica task is able to empty the swap.

In some cases, the swap is currently used and the automatic cleaning could make the system unstable :

Example in syslog:

Sep 12 09:05:14 exchange exec.status.php[1179]: SwapWatchdog:: Starting to purge the swap file because it execeed rules
Sep 12 09:06:24 exchange kernel: [ 9012.062353] mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0
Sep 12 09:06:24 exchange kernel: [ 9012.062372] mysqld cpuset=/ mems_allowed=0
Sep 12 09:06:24 exchange kernel: [ 9012.062382] Pid: 1477, comm: mysqld Not tainted 2.6.32-5-xen-amd64 #1
Sep 12 09:06:24 exchange kernel: [ 9012.062392] Call Trace:
Sep 12 09:06:24 exchange kernel: [ 9012.062407]  [<ffffffff810b74b4>] ? oom_kill_process+0x7f/0x23f
Sep 12 09:06:24 exchange kernel: [ 9012.062419]  [<ffffffff810b79d8>] ? __out_of_memory+0x12a/0x141
Sep 12 09:06:24 exchange kernel: [ 9012.062430]  [<ffffffff810b7b2f>] ? out_of_memory+0x140/0x172

You need to personnalize the Swap Watchdog in order to resolve the issue.

  • Click on System information.
  • Select Your server tab.
  • Click on Display Memory icon

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  • This feature will check the Swap system each 30Mn and clean it according limits sets.
    0 in the Max size field means that only pourcentage is used to calculate the limit.
    If you set a value in this field, the robot will use the Max size in MB has the main limit instead the pourcentage.
  • You can disable this feature if you did not want Artica to perform Automatic Swap cleaning task

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