14.4 High CPU ARC issue

[Paul Macdonald]

Posting in case it helps someone.

We had a a couple of boxes displaying unusally high cpu ( specifically
system loads)

After spotting the link below, we resolved by increasing the ARC max

https://forums.freebsd.org/threads/high-cpu-and-severe-slowdown-on-freebsd-14-4-openzfs-2-2-9-with-lower-vfs-zfs-arc-max.102233/

Paul


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Paul Macdonald
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[Christos Chatzaras]

> On 27 Apr 2026, at 12:18, Paul Macdonald <pa...@ifdnrg.com> wrote:
>
> Posting in case it helps someone.
>
> We had a a couple of boxes displaying unusally high cpu ( specifically system loads)
>
> After spotting the link below, we resolved by increasing the ARC max
>
> https://forums.freebsd.org/threads/high-cpu-and-severe-slowdown-on-freebsd-14-4-openzfs-2-2-9-with-lower-vfs-zfs-arc-max.102233/

I am the one who created that FreeBSD forum thread. I also opened a bug report with OpenZFS here:

https://github.com/openzfs/zfs/issues/18397

In my case, to fix the issue I disabled setting a custom value for vfs.zfs.arc.max