Re:ZFS 2.3.0 released with ZFS raidz expansion
by taskforcegemini on Tuesday January 14, 2025 @01:42PM
(#42701813)
what's the best way to deal with this then? disable filecache of linux?
I've tried disabling/minimizing arc in the past to avoid the oom reaper, but the arc was stubborn and its RAM usage remained as is
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Re:ZFS 2.3.0 released with ZFS raidz expansion
by ssl-3 on Tuesday January 14, 2025 @02:43PM
(#42702732)
I didn't have any trouble limiting zfs_arc_max to 3GB on one system where I felt that it was important. I ran it that way for a fair number of years and it always stayed close to that bound (if it was ever exceeded, it wasn't by a noteworthy amount at any time when I was looking).
At the time, I had it this way because I had fear of OOM events causing [at least] unexpected weirdness.
A few months ago I discovered weird issues with a fairly big, persistent L2ARC being ignored at boot due to insufficient ARC. So I stopped arbitrarily limiting zfs_arc_max and just let it do its default self-managed thing.
So far, no issues. For me. With my workload.
Are you having issues with this, or is it a theoretical problem?
Re:ZFS 2.3.0 released with ZFS raidz expansion
by ryao on Tuesday January 14, 2025 @02:57PM
(#42702945)
These days, ZFS frees memory fast enough when Linux requests memory to be freed that you generally do not see OOM because of ZFS, but if you have a workload where it is not fast enough, you can limit the maximum arc size to try to help:
https://openzfs.github.io/openzfs-docs/Performance%20and%20T...