On Mon, Mar 03, 2008 at 08:27:08AM -0800, Richard Elling wrote: > me wrote: > >> All that said, I'm still occasionally tempted to bring it back. > >> It may become more relevant with flash memory as a storage medium. > > > > How common would be single on-disk bit flips in 128K blocks? > > Most enterprise class disks are rated at 1 uncorrectable read error for > 10^15 > bits(!) read. For a 1 TByte disk, that means you can expect an > uncorrectable > read error about once for every 175 times you read the entire disk. > Contrast > this to consumer class disks which are UER 1 in 10^14, or 17 times for a > 1 TByte disk.
I take it that that would mean that the block would be unreadable, rather than readable with incorrect data. That would be based on the CRC included with each disk block. So, the granularity is really at the block level. You probably can't even read a bad block from a disk. -- -Gary Mills- -Unix Support- -U of M Academic Computing and Networking- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
