Proxmox backups leaving behind lots of cache

[bobdog]

So I have been doing some testing with backups, I schedule 2 backups to run under the same job last night, and upon running it seemingly used a lot of cache.





Is this anything to be concerned about? or will this all get written back to disk or just clear out automatically as more actual ram overwrites it?
If not, how can we have the inactive ram clear out to become available again.
the good thing is that its not going into swap as i already have it set swappniess to 1, but for most people where the default is 60, i could see this causing performance issues with backups for most users.

 

[bobdog]

Ok well side note, just checked another server, this one runs a ZFS pool, ran 1 backup on a tiny VM that is 10gb in size, this one increased the ram by a ton, do we need to tweak arc cache to not have this happen with servers running a ZFS pool?

 

[LnxBil]

You may read up on what cache is used for. A good starting point is always:

https://www.linuxatemyram.com/

 

[bobdog]

You may read up on what cache is used for. A good starting point is always:

https://www.linuxatemyram.com/

Ah ok was thinking as much, just wanted to make sure as typically before what would happen is we would have issues with it overflowing into swap, which then would sometimes be a bit too much for the CPU getting to busy with IO, causing things to slow down even more taking hours for not a lot of data to backup.
but for the other server in the case where it backed up a single VM with 10gb of data
backup started at midnight, and it is now "used" not cached, but rather used, 40gb of used ram for backing up a 10gb VM

total used free shared buff/cache available
Mem: 136848 95095 2021 62 39731 40541
Swap: 8191 1 8190



I'm assuming this is because of default settings with arc cache?