On Sun, Jul 4, 2010 at 11:28 AM, Bob Friesenhahn <bfrie...@simple.dallas.tx.us> wrote: >> >> Ok... so we've rebuilt the pool as 14 pairs of mirrors, each pair having >> one disk in each of the two JBODs. Now we're getting about 500-1000 IOPS >> (according to zpool iostat) and 20-30MB/sec in random read on a big >> database. Does that sounds right? > > I am not sure who wrote the above text since the attribution quoting is all > botched up (Gmail?) in this thread. Regardless, it is worth pointing out > that 'zpool iostat' only reports the I/O operations which were actually > performed. It will not report the operations which did not need to be > performed due to already being in cache. A quite busy system can still > report very little via 'zpool iostat' if it has enough RAM to cache the > requested data. > > Bob
Very good point. You can use a combination of "zpool iostat" and fsstat to see the effect of reads that didn't turn into physical I/Os. -- Mike Gerdts http://mgerdts.blogspot.com/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
