On Tue, 15 Apr 2008, Keith Bierman wrote: > > Perhaps providing the computations rather than the conclusions would be more > persuasive on a technical list ;>
No doubt. The computations depend considerably on the size of the disk drives involved. The odds of experiencing media failure on a single 1TB SATA disk are quite high. Consider that this media failure may occur while attempting to recover from a failed disk. There have been some good articles on this in USENIX Login magazine. ZFS raidz1 and raidz2 are NOT directly equivalent to RAID5 and RAID6 so the failure statistics would be different. Regardless, single disk failure in a raidz1 substantially increases the risk that something won't be recoverable if there is a media failure while rebuilding. Since ZFS duplicates its own metadata blocks, it is most likely that some user data would be lost but the pool would otherwise recover. If a second disk drive completely fails, then you are toast with raidz1. RAID5 and RAID6 rebuild the entire disk while raidz1 and raidz2 only rebuild existing data blocks so raidz1 and raidz2 are less likely to experience media failure if the pool is not full. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
