zfs_arc_max realtime

spearox

Renowned Member
Jun 6, 2013
89
2
73
Dear Members,

I would like to ask about the /etc/modprobe.d/zfs.conf
Can I change the options zfs zfs_arc_max=X parameter realtime somehow? There are running VM's and I don't would like to restart.

Thanks.
 
No, the options are loaded when the module is inserted into the kernel.
 
Ehm, you can w/o reboot by:

echo "your wanted size in byte" > /sys/module/zfs/parameters/zfs_arc_max

and a

echo 3 > /proc/sys/vm/drop_caches

Thanks!

Can you tell me please what this do exactly? "echo 3 > /proc/sys/vm/drop_caches"
 
Well, if you want to decrease your ARC, you need to free the already allocated memory.

https://linux-mm.org/Drop_Caches

Running that drop_caches command _should_ free the reclaimable RAM from the ARC. There are some deficiencies in the ZFS on Linux memory management though, which could cause this *not* to happen

To set the max_size "more save" w/o a host reboot, you could just un-/ and reload zfs module, but forsure this needs to shutdown all processes which use ZFS (e.g. your VMs on ZFS pool)
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!