On Sat, Oct 22, 2011 at 12:36 AM, Paul Kraus <p...@kraus-haus.org> wrote:

> Recently someone posted to this list of that _exact_ situation, they loaded
> an OS to a pair of drives while a pair of different drives containing an OS
> were still attached. The zpool on the first pair ended up not being able to
> be imported, and were corrupted. I can post more info when I am back in the
> office on Monday.

    See the thread started on Tue, Aug 2, 2011 at 12:23 PM with a
Subject of "[zfs-discuss] Wrong rpool used after reinstall!", the
followups, and at least one additional related thread.

    While I agree that you _should_ be able to have multiple unrelated
boot environments on hard drives at once, it seems prudent to me to
NOT do such. I assume you _can_ manage multiple ZFS based boot
environments using Live Upgrade (or whatever has replaced it in 11).
NOTE that I have not done such (managed multiple ZFS boot environments
with Live Upgrade), but I ASSUME you can.

    I suspect that the "root" of this potential problem is in the ZFS
boot code and the use of the same zpool name for multiple zpools at
once. By having the boot loader use the zpool directly you get the
benefit of having the redundancy of ZFS much earlier in the boot
process (the only thing that appears to load off of a single drive is
the boot loader, everything from there on loads from the mirrored
zpool, at least on my NCP 3 system, my first foray into ZFS root). The
danger is that if there are multiple zpools with the same (required)
name, then the boot loader may become confused, especially if drives
get physically moved around.

Paul Kraus
-> Senior Systems Architect, Garnet River ( http://www.garnetriver.com/ )
-> Sound Coordinator, Schenectady Light Opera Company (
http://www.sloctheater.org/ )
-> Technical Advisor, RPI Players
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