ZFS doesn't mountroot: Unable to open /dev/ad4p3 for writing (error=1).

[Yuri Pankov]

James R. Van Artsdalen <james-freebsd-fs2 <at> jrv.org> writes:

> 
> FreeBSD 9.0-svn207742 #0: Sat May  8 17:13:06 UTC 2010
> root <at> clunk.housenet.jrv:/usr/obj/usr/src/sys/GENERIC amd64
> 
> I am no longer able to boot my newly-created ZFS pools in a VirtualBox
> VM: the "Unable to open /dev/ad4p3 for writing" error shown below
> prevents the pool from being imported even though it is found.
> 
> When the pool was created it was on disk ad6, but it is now booting on
> ad4: zpool.cache contains wrong disk names so the kernel finds the pool
> member(s) by guid, not name.
<snip>

Same here on recent -CURRENT. I recently needed to disable ahci(4) driver (pool
was created on ada0p3), and got the same error about ad4p3 (device name without
ahci driver).

Yuri