On Tue, 16 Mar 2010, Tonmaus wrote:
This wasn't mirror vs. raidz but raidz1 vs. raidz2, whereas the latter maxes out CPU and the former maxes out physical disc I/O. Concurrent payload degradation isn't that extreme on raidz1 pools, as it seems. Hence, the CPU theory that you still seem to be reluctant to follow.
If CPU is maxed out then that usually indicates some severe problem with choice of hardware or a misbehaving device driver. Modern systems have an abundance of CPU.
I don't think that the size of the pool is particularly significant since zfs scrubs in a particular order and scrub throughput is dicated by access times and bandwidth. In fact there should be less impact from scrub in a larger pool (even though scrub may take much longer) since the larger pool will have more vdevs. The vdev design is most important. Too many drives per vdev leads to poor performance, particularly if the drives are huge sluggish ones.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, 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
