[PVE-User] A less aggressive OOM?

[Marco Gaiarin]

Mandi! dorsy via pve-user
  In chel di` si favelave...

Thanks to all, particulary to Victor for the wonderful analisys, that lead
me to learn a bit better OOM dump...

>> if OOM kicks in because half of the ram is being used for 
>> caches/buffers, i would blame OOMkiller or ZFS for tha. The problem 
>> should be resolved at zfs or memory management level.

> Absolutely no!
> You are responsible for giving ZFS the limits. As even described in the 
> proxmox documentation here:
> https://pve.proxmox.com/wiki/ZFS_on_Linux#sysadmin_zfs_limit_memory_usage

I'm a bit in the side of Roland on this. ARC is a (indeed, complex)
buffer/cache, so seems reasonably that, if i need to sacrifice something, it
is better to sacrifice cache than VM.

Aniway, if i understood well, default ZFS was to have ARC at 50% of the RAM;
after PVE 8.1, PVE modify the default to 10% (for new installation); there's
also a 'rule of thumb' to setup ARC, so 10% is somewhat a 'starting point'.


In some server i can setup easily swap (i have a disk for an L2ARC, so i can
simply detach, partition a bit and reattach as L2ARC and swap).
Clearly, i'll set swappiness at 1, to be used only when strictly needed.


Thanks to all!

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