I have a linux box that is used as SAN storage. It is equipped with 14 SATA HDDs and the only software it run is iscsi target and zabbix agent. This is physical box, not VM.
The RAM size installed is 128 GB, swap was arranged of 4 GB and no-one ever care for its size when RAM is quite big, but as the box run (the uptime is 694 days) swap was used more and more, and now it used for ~80%.
The htop won't show anything bad, looks like OS uses RAM as cache etc.
swappiness was set to 10, then to 1, none helped. Surely I can disable swap completely but looks like this will be bad move.
So my question is simple, how can I set the box to use RAM and not use swap, and why it uses swap at all while RAM is enough?
This is SAN, so it serves blocks not files, so cache can be done on block bases, and can easily be reduced if RAM is limited, it won't impact the logic of iSCSI anyway.
Zabbix says right now I have RAM available = 123.22 GB (hey, almost all of 128 GB!), swap used is 3.24 GB of 4 GB.