[zfs-discuss] ZFS Mirror Problem

Richard Elling
Mon, 16 Jun 2008 21:49:30 -0000

Matthew C Aycock wrote:
> Well, I have a zpool created that contains four vdevs. Each Vdev is a
mirror of a T3B lun and a corresponding lun of a SE3511 brick. I did this since
I was new with ZFS and wanted to ensure that my data would survive an array
failure. It turns out that I was smart for doing this :)
>
> I had a hardware failure on the SE3511 that caused the complete RAID5 lun
on the se3511 to die. (The first glance showed 6 drives failed :( ) However, I
would have expected that ZFS would detect the failed mirror halves and offline
them as would ODS and VxVM. To my shock, it basically hung the server. I
eventually had to unmap the SE3511 luns and replace them space I had available
from another brick in the SE3511. I then did a zpool replace and ZFS reslivered
the data.
>
> So, why did ZFS hang my server?
>

It was patiently waiting.

> This is on Solaris 11/06 kernel patch 127111-05 and ZFS version 4.
>
>

Additional failure management improvements were integrated
into NV b72 (IIRC).  I''m not sure when or if those changes will
make it into Solaris 10, but update 6 would be a good guess.
 -- richard