News for hackers. Stuff that matters.

A comment on Why are my ZFS disks so noisy?. Parent comment

Re:Why are my ZFS disks so noisy? by usefulcat on Friday September 27, 2024 @10:03AM (#41670627)
With ZFS that wouldn't necessarily help. I've been using ZFS at work for many years with mostly large files. Even if I repeatedly read the same file as fast as possible, ZFS will not cache the entire thing in memory (there's no shortage of RAM so that's not it). This is unlike most linux filesystems, which are usually pretty aggressive with caching.

Maybe there is some combination of settings that will get it to cache more aggressively; just saying that it's not a given that it will do so.

[ Parent | on HN ]
Re:Why are my ZFS disks so noisy? by kaliszad on Saturday September 28, 2024 @06:52PM (#41683483)
The ZFS ARC cache tries to keep a balance between most frequently and least recently used data. Also, by default, ZFS ARC only fills out to a maximum of about half the available RAM. You can change that at runtime (by writing the size in bytes to

  /sys/module/zfs/parameters/zfs_arc_max
or setting the module e.g. in

  /etc/modporbe.d/zfs.conf
to something like this

  options zfs zfs_arc_max=<size in bytes>
). But be careful, as the ZFS ARC does not play that nice with the OOM killer.
[ Parent | on HN ]