Re: zfs and device name changes

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Tue, 24 Mar 2026 09:14:37 +0900
> From: Takashi YAMAMOTO <yamt9999%gmail.com@localhost>
> 
> the attached patch is my attempt to make zfs a bit more robust against
> device name changes.
> the identical patch is available at github too:
> https://github.com/yamt/netbsd-src/commit/32283c2e362034301c3da218a05849c04ee20c2a
> 
> while it seems working as far as i tested, i'd be happy if someone can review it
> as my knowledge of zfs (well, and recent netbsd in general) is weak.

I don't understand why all this new code is needed.  Doesn't zfs
already have logic to scan all disks/partitions/wedges and find the
vdevs by guid?

I am under the impression that /etc/zfs/zpool.cache may bypass the
scan so this doesn't work in some circumstances, but in my years of
using zfs on various machines with frequent device renumbering of cgd
volumes and dkN wedges, I have never encountered this type of trouble
myself, and I'm not sure what I'm doing differently.