ZFS Cache Limit

[Mr Q]

Hi there,

 

Why is ZFS Cache limit to 32Gb?

Can we change this, i have 256Gb ram in my main server and want to use at least 128Gb for ZFS Cache, is this possible

 

Greetings

Mr Q

Edited July 8, 2023 by Mr Q

[david279]

Read the release page for 6.12 they set limits(1/4 of total ram) for the 16 32 GB users so that zfs doesn't gobble all their ram. They explain how to change it to what you want in the release notes. 

[Mr Q]

1 minute ago, david279 said:

Read the release page for 6.12 they set limits(1/4 of total ram) for the 16 32 GB users so that zfs doesn't gobble all their ram. They explain how to change it to what you want in the release notes. 

hi david, thanks for the reply, but 1/4 of 256 is 64, so why is my zfs cache limit 32?

[david279]

Oh I got it wrong too it's 1/8 of total ram. 

 

https://docs.unraid.net/unraid-os/release-notes/6.12.0/

[Mr Q]

3 minutes ago, david279 said:

Oh I got it wrong too it's 1/8 of total ram. 

 

https://docs.unraid.net/unraid-os/release-notes/6.12.0/

found it

 

During system boot, the file /etc/modprobe.d/zfs.conf is auto-generated to limit the ZFS ARC to 1/8 of installed memory. This can be overridden if necessary by creating a custom 'config/modprobe.d/zfs.conf' file. Future update will include ability to configure the ARC via webGUI, including auto-adjust according to memory pressure, e.g., VM start/stop

 

thanks