On Tue, 26 Feb 2013, hagai wrote:
for what is worth.. I had the same problem and found the answer here - http://forums.freebsd.org/showthread.php?t=27207
Given enough sequential I/O requests, zfs mirrors behave every much like RAID-0 for reads. Sequential prefetch is very important in order to avoid the latencies.
While this script may not work perfectly as is for FreeBSD, it was very good at discovering a zfs performance bug (since corrected) and is still an interesting exercise for zfs to see how ZFS ARC caching helps for re-reads. See "http://www.simplesystems.org/users/bfriesen/zfs-discuss/zfs-cache-test.ksh";. The script will exercise an initial uncached read from disks, and then a (hopefully) cached re-read from disks. I think that it serves as a useful benchmark.
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
