Re: zpool geli encryption question

From: void <void_at_f-m.fm>
Date: Sun, 15 Oct 2023 16:39:22 UTC
On Sun, Oct 15, 2023 at 07:17:57AM -0700, Alan Somers wrote:

>How much of the FreeBSD VM's disk is actually in-use?

(in the example below, another vm instance, same observation)

from the host:

NAME                   USED    AVAIL REFER  MOUNTPOINT
ssdzfs/fbsd140Rv1       97.5G   309G  21.3G  -

within the booted vm:

NAME                AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD
zroot               74.8G  9.97G        0B     96K             0B      9.97G
zroot/ROOT          74.8G  4.61G        0B     96K             0B      4.61G
zroot/ROOT/default  74.8G  4.61G        0B   4.61G             0B         0B
zroot/home          74.8G  59.6M        0B   59.6M             0B         0B
zroot/tmp           74.8G   120K        0B    120K             0B         0B
zroot/usr           74.8G  5.28G        0B     96K             0B      5.28G
zroot/usr/ports     74.8G  5.28G        0B   5.28G             0B         0B
zroot/usr/src       74.8G    96K        0B     96K             0B         0B
zroot/var           74.8G  1.17M        0B     96K             0B      1.08M
zroot/var/audit     74.8G    96K        0B     96K             0B         0B
zroot/var/crash     74.8G    96K        0B     96K             0B         0B
zroot/var/log       74.8G   564K        0B    564K             0B         0B
zroot/var/mail      74.8G   252K        0B    252K             0B         0B
zroot/var/tmp       74.8G    96K        0B     96K             0B         0B

gzipped archive:

-rw-r--r--   1 root wheel   21G 15 Oct 16:39 2023.10.15_15:57.fbsd140Rv1.gz

>Maybe you are using TRIM with FreeBSD, which punches holes in the host's ZFS
>storage.  

On the bhyve host (14.0-BETA3 #0 releng/14.0-n265111)

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
vfs.ffs.dotrimcons: 1

Does this mean trim is enabled and active on the host?
I didn't set it. Maybe it was automatically set because zfs knows the
hardware is SSD?

> That would explain why compression seems to save space, even
> though the data is encrypted.

That's really smart.

TYVM for the explainer.
--