On Apr 18, 2010, at 5:23 AM, Edward Ned Harvey wrote: >> From: Richard Elling [mailto:richard.ell...@gmail.com] >> >> On Apr 17, 2010, at 11:51 AM, Edward Ned Harvey wrote: >> >>> For zpool < 19, which includes all present releases of Solaris 10 and >>> Opensolaris 2009.06, it is critical to mirror your ZIL log device. A >> failed >>> unmirrored log device would be the permanent death of the pool. >> >> I do not believe this is a true statement. In large part it will depend >> on >> the nature of the failure -- all failures are not created equal. It has >> also >> been shown that such pools are recoverable, albeit with tedious, manual >> procedures required. Rather than saying this is a "critical" issue, I >> could >> say it is "preferred." Indeed, there are *many* SPOFs in the typical >> system >> (any x86 system) which can be considered similarly "critical." > > Could you please describe a type of failure of an unmirrored log device in > zpool < 19 which does not result in the pool being faulted and unable to > import? I don't know of any.
The most common failure mode on HDDs and, it seems, SSDs is a nonrecoverable read. A nonrecoverable read failure on your separate log device will not cause the pool to fail import. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance Las Vegas, April 29-30, 2010 http://nexenta-vegas.eventbrite.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
