Hi Scott, Try disabling compression if it is on. Had a customer who found performance would tank dramatically once zpool hit around 70% full. Patched, tuned, sep zil etc., but nothing returned a positive impact. However, once compression was disabled, blammo i/o performance returned to expected throughput.
Worth a try, Andrew On 01/20/10 09:24 AM, Scott Duckworth wrote: > [Cross-posting to ldoms-discuss] > > We are occasionally seeing massive time-to-completions for I/O requests on > ZFS file systems on a Sun T5220 attached to a Sun StorageTek 2540 and a Sun > J4200, and using a SSD drive as a ZIL device. Primary access to this system > is via NFS, and with NFS COMMITs blocking until the request has been sent to > disk, performance has been deplorable. The NFS server is a LDOM domain on > the T5220. > > To give an idea of how bad the situation is, iotop from the DTrace Toolkit > occasionally reports single I/O requests to 15k RPM FC disks that take more > than 60 seconds to complete, and even requests to a SSD drive that take over > 10 seconds to complete. It's not uncommon to open a small text file using > vim (or similar editor) and nothing to pop up for 10-30 seconds. Browsing > the web becomes a chore, as the browser locks up for a few seconds after > doing anything. > > I have a full write-up of the situation at > http://www.cs.clemson.edu/~duckwos/zfs-performance/. Any thoughts or > comments are welcome. > -- <http://www.sun.com> * Andrew Foote * Systems Engineer *Sun Microsystems, Inc.* Level 7, 476 St.Kilda Rd Melbourne, Victoria 3004 Australia Phone x59253/+61 3986962 53 Mobile 0404 815 822 Fax 0061398696209 Email Andrew.Foote at Sun.COM <http://www.sun.com> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/ldoms-discuss/attachments/20100120/5cbf41af/attachment.html>
