Help ZFS FreeBSD 8.0 RC2 Write performance issue

[Artem Belevich]

2009/11/12 Dag-Erling Smørgrav <des at des.no>:
> The zpool(1M) manpage seems to disagree:
>
>       Log  devices  can  be added, replaced, attached, detached, and imported
>       and exported as part of the larger pool.

Solaris' man page has somewhat different wording -- it indicates that
only part of mirrored log device can be removed. See
http://docs.sun.com/app/docs/doc/819-2240/zpool-1m

In any case the reality is that you can not remove log vdev from the pool:

$ zpool status z1
  pool: z1
 state: ONLINE
 scrub: none requested
config:

	NAME         STATE     READ WRITE CKSUM
	z1           ONLINE       0     0     0
	  mirror     ONLINE       0     0     0
	    ada3p3   ONLINE       0     0     0
	    ada2p3   ONLINE       0     0     0
	logs         ONLINE       0     0     0
	  gpt/zil    ONLINE       0     0     0
	cache
	  gpt/l2arc  ONLINE       0     0     0

errors: No known data errors
$ zpool remove z1 gpt/zil
Password:
cannot remove gpt/zil: only inactive hot spares or cache devices can be removed

--Artem