Bob Friesenhahn wrote: > On Tue, 15 Apr 2008, Maurice Volaski wrote: > >> 4 drive failures over 5 years. Of course, YMMV, especially if you >> drive drunk :-) >> > > Note that there is a difference between drive failure and media data > loss. In a system which has been running fine for a while, the chance > of a second drive failing during rebuild may be low, but the chance of > block-level media failure is not. >
I couldn't have said it better myself :-). The prevailing studies are clearly showing unrecoverable reads as the most common failure mode. > However, computers do not normally run in a vaccum. Many failures are > caused by something like a power glitch, temperature cycle, or the > flap of a butterfly's wings. Unless your environment is completely > stable and the devices are not dependent on some of the same things > (e.g. power supplies, chassis, SATA controller, air conditioning) then > what caused one device to fail may very well cause another device to > fail. > Add to this manufacturing vintage. We do see some vintages which have higher incidence rates than others. It is not often practical to get all the disks in a system to be from different vintages, especially on a system like the X4500. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
