On Oct 12, 2010, at 8:21 AM, "Edward Ned Harvey" <sh...@nedharvey.com> wrote:
>> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- >> boun...@opensolaris.org] On Behalf Of Stephan Budach >> >> c3t2100001378AC0253d0 ONLINE 0 0 0 > > How many disks are there inside of c3t2100001378AC0253d0? > > How are they configured? Hardware raid 5? A mirror of two hardware raid > 5's? The point is: This device, as seen by ZFS, is not a pure storage > device. It is a high level device representing some LUN or something, which > is configured & controlled by hardware raid. > > If there's zero redundancy in that device, then scrub would probably find > the checksum errors consistently and repeatably. > > If there's some redundancy in that device, then all bets are off. Sometimes > scrub might read the "good half" of the data, and other times, the bad half. > > > But then again, the error might not be in the physical disks themselves. > The error might be somewhere in the raid controller(s) or the interconnect. > Or even some weird unsupported driver or something. If it were a parity based raid set then the error would most likely be reproducible, if not detected by the raid controller. The biggest problem is from hardware mirrors where the hardware can't detect an error on one side vs the other. For mirrors it's always best to use ZFS' built-in mirrors, otherwise if I were to use HW RAID I would use RAID5/6/50/60 since errors encountered can be reproduced, two parity raids mirrored in ZFS would probably provide the best of both worlds, for a steep cost though. -Ross _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
