On Mar 10, 2010, at 4:18 PM, Chris Banal wrote: > What is the best way to tell if your bound by the number of individual > operations per second / random io?
If no other resource is the bottleneck :-) > "zpool iostat" has an "operations" column but this doesn't really tell me if > my disks are saturated. Traditional "iostat" doesn't seem to be the greatest > place to look when utilizing zfs. Observe the relationship between iops and asvc_t. You want your asvc_t to be as low as possible. HDDs are not well modeled by a simple queue, which is what iostat shows. There are some SSDs, like the DDRdrive X1, which are well modeled by a simple queue (and are blazing fast :-). For HDDs look for asvc_t well below 15 ms and for SSDs look for asvc_t less than 1 ms. Note: iostat will only show 0.1 ms resolution, which doesn't work so well for fast SSDs :-) If you want to dig farther, there are some dtrace tools which will show spatial distribution, size, queue depths, and pretty much anything else you can think of. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance http://nexenta-atlanta.eventbrite.com (March 16-18, 2010) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
