On 5/2/2024 10:16 AM, Warner Losh wrote:
When trims are fast, you want to send them to the drive as soon as you
know the blocks are freed. UFS always does this (if trim is enabled at
all).
ZFS has a lot of knobs to control when / how / if this is done.
vfs.zfs.vdev.trim_min_active: 1
vfs.zfs.vdev.trim_max_active: 2
vfs.zfs.trim.queue_limit: 10
vfs.zfs.trim.txg_batch: 32
vfs.zfs.trim.metaslab_skip: 0
vfs.zfs.trim.extent_bytes_min: 32768
vfs.zfs.trim.extent_bytes_max: 134217728
vfs.zfs.l2arc.trim_ahead: 0
I've not tried to tune these in the past, but you can see how they affect
things.
Thanks Warner, I will try and play around with these values to see if
they impact things. BTW, do you know what / why things would be
"skipped" during trim events ?
kstat.zfs.zrootoffs.misc.iostats.trim_bytes_failed: 0
kstat.zfs.zrootoffs.misc.iostats.trim_extents_failed: 0
kstat.zfs.zrootoffs.misc.iostats.trim_bytes_skipped: 5968330752
kstat.zfs.zrootoffs.misc.iostats.trim_extents_skipped: 503986
kstat.zfs.zrootoffs.misc.iostats.trim_bytes_written: 181593186304
kstat.zfs.zrootoffs.misc.iostats.trim_extents_written: 303115
