Swap may be used when there isn't enough RAM available for the running processes on a server. The following warnings are presented as swap usage increases:

Remediation

Swap memory is used by Linux over the course of normal operation, but it does not get relinquish automatically. If you are receiving these alerts often, but they seem to clear automatically, it may be due to temporary memory spikes and may be resolved by resetting swap.

To reset your swap memory, first check that you have enough available physical memory to store the swap with the command free -m

root@deskpro:/# free -m
              total        used        free      shared  buff/cache   available
Mem:           3931        2115         241         141        1575        1394
Swap:          3930         957        2973
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In the example above, 957MB of swap memory is used, but we have 1394MB of physical memory available .

We can now turn off swap with the command swapoff -a, checking repeatedly with free -m to confirm the used swap decreases to 0, and the available memory has decreased as the data is moved.

root@deskpro:/# free -m
              total        used        free      shared  buff/cache   available
Mem:           3931        2842         116         273         972         540
Swap:             0           0           0
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Finally, once the swap has cleared, you can turn it back on with the command swapon -a, and you should see that the used swap memory is back down to 0MB:

root@deskpro:/# free -m
              total        used        free      shared  buff/cache   available
Mem:           3931        2839         189         273         902         543
Swap:          3930           0        3930
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If you continue to have issues with swap after a reset, it may be that you do not have enough memory available for your helpdesk to run optimally, and you may be required to increase the physical memory allocated to your server.