Re: OpenZFS and L2ARC

On 08/09/2020 08:43, Stefan Esser wrote:
> OpenZFS seems to work quite well for me, in general, but I have 
> questions regarding the L2ARC statistics.
>
…

> The sysutils/zfs-stats port reports the following values for
> this system, BTW:
>
> ------------------------------------------------------------------------
> ZFS Subsystem Report                Tue Sep  8 09:02:46 2020
> ------------------------------------------------------------------------
>
…

>
> Quite a number of sysctl variable names have changed, and the port
> needs to be adapted to the new names (therefore there are lots of 0
> values in the -L output).
>
> The following names used by zfs-stats do not exist in OpenZFS:
>
> kstat.zfs.misc.arcstats.recycle_miss
> kstat.zfs.misc.arcstats.l2_write_buffer_bytes_scanned
> kstat.zfs.misc.arcstats.l2_write_buffer_iter
> kstat.zfs.misc.arcstats.l2_write_buffer_list_iter
> kstat.zfs.misc.arcstats.l2_write_buffer_list_null_iter
> kstat.zfs.misc.arcstats.l2_write_full
> kstat.zfs.misc.arcstats.l2_write_in_l2
> kstat.zfs.misc.arcstats.l2_write_io_in_progress
> kstat.zfs.misc.arcstats.l2_write_not_cacheable
> kstat.zfs.misc.arcstats.l2_write_passed_headroom
> kstat.zfs.misc.arcstats.l2_write_pios
> kstat.zfs.misc.arcstats.l2_write_spa_mismatch
> kstat.zfs.misc.arcstats.l2_write_trylock_fail
> kstat.zfs.misc.arcstats.l2_writes_hdr_miss
> vfs.zfs.vdev.cache.size
>
> The existence of vfs.zfs.vdev.cache.size vs vfs.zfs.vdev.cache_size
> can be used to detect OpenZFS, and is easily fixed.
>
> But the above listed L2ARC values seem to have been removed from or
> have never existed in OpenZFS, and I did not find any substitutes.
>
> Are there any plans to re-create them in OpenZFS on FreeBSD or are
> they gone for good?

Recalling 
<https://lists.freebsd.org/pipermail/freebsd-current/2020-March/075661.html>, 
on 28/03/2020 15:17,28/03/2020 15:17, Allan Jude wrote:

 >> …
 >>
 >> Basically 'arc' was converted to a subtree.
 >>
 >> We should add some backwards compat sysctls to cover some of
 >> these renames etc so configs and scripts don't break etc.

>
> I'd like to update the zfs-stats port for compatibilíty with OpenZFS ...
>
Cool!