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vfs.zfs.arc_max ignored

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE

crkinard

Explorer
Joined
Oct 24, 2019
Messages
79
Trying to increase RAM usage when it comes to the ARC. Setting ti higher than the default half my RAM.

System Settings -> Advanced -> Sysctl

Reboot and there is no change in usage or in 'arc_summary -s arc'.
Am I doing something wrong?
 

cwagz

Dabbler
Joined
Jul 3, 2022
Messages
31
I think it gets reset every time you start or stop a VM. Maybe even on a schedule. I could not get a change to stick.
 

HunorR

Dabbler
Joined
Jun 30, 2022
Messages
13
Personally i just added the following line to Init/Shutdown Script`s : echo 34359738368 > /sys/module/zfs/parameters/zfs_arc_max
and it works for me
 

Etorix

Guru
Joined
Dec 30, 2020
Messages
1,012
Read here:
The cap at half the RAM in SCALE is forced upon by the Linux kernel allocator. (CORE can have a higher limit :wink:)
 

crkinard

Explorer
Joined
Oct 24, 2019
Messages
79
Personally i just added the following line to Init/Shutdown Script`s : echo 34359738368 > /sys/module/zfs/parameters/zfs_arc_max
and it works for me
Thats what I was doing but I thought it was not the 'proper' way to do it.
Read here:
The cap at half the RAM in SCALE is forced upon by the Linux kernel allocator. (CORE can have a higher limit :wink:)
Ahh so its not just the default. It is the 'forced default'.
 
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