ZFS arcstat max

[Tdreissi]

Hi,

I am running several proxmox servers with ZFS.
With my last two servers I have problems with "zfs_arc_max"

All values are properly maintained, but they don't work.
Target value should be 16GiB.

cat /etc/modprobe.d/zfs.conf
options zfs zfs_arc_max=17179869184

cat /sys/module/zfs/parameters/zfs_arc_max
17179869184

arcstat
time read miss miss% dmis dm% pmis pm% mmis mm% arcsz c
19:50:48 0 0 0 0 0 0 0 0 0 299M 755G

A "update-initramfs -u" and reboot doesn't help.

zfs --version
zfs-0.8.4-pve2
zfs-kmod-0.8.4-pve1

pveversion
pve-manager/6.2-12/b287dd27 (running kernel: 5.4.65-1-pve)

Does somebody has any idea

 

[leesteken]

Please check if zfs_arc_min is less than zfs_arc_max, otherwise ZFS will use more memory than zfs_arc_max.

 

[Tdreissi]

Hi,

cat /sys/module/zfs/parameters/zfs_arc_min
0

I never set the value for "zfs_arc_min".
Works with the other 5 servers without problems.

arc_summary
Min size (hard limit): 6.2 % 47.2 GiB
Max size (high water): 16:1 755.2 GiB

That could be the problem. The "min" size used is larger than the "max" value set.
How can I change this?

Thanks for help....

 

[leesteken]

That could be the problem. The "min" size used is larger than the "max" value set.
How can I change this?

Set the zfs_arc_min just like zfs_arc_max but lower.
Also run update-initramfs -u and reboot.

 

[Tdreissi]

Didn't really help.
"min" value is 16GB now - but not max

arc_summary
Min size (hard limit): 2.1 % 16.0 GiB
Max size (high water): 47:1 755.2 GiB

options zfs zfs_arc_min=17179869184
options zfs zfs_arc_max=17179869184

 

[leesteken]

options zfs zfs_arc_min=17179869184
options zfs zfs_arc_max=17179869184

I think, in order to pass both parameters to the same module, you need to put them on the same line. Like this; options zfs zfs_arc_min=17179869184 zfs_arc_max=17179869184