[OpenIndiana-discuss] Pool I/O

[Joe Hetrick]

Hi all,


	We've recently run into a situation where I'm seeing pool at 90-100 %b, and our ZIL's at 90-100 %w, yet all of the spindles are relatively idle.  Furthermore, local I/O is normal, and testing is able to quickly and easily put both pool and spindles in the VDEV into high activity.

    The system is primarily accessed via NFS (home server for an HPC environment).  We've had users to evil things before to cause pain, but, this is most odd, as I would only expect this behavior if we had a faulty device in the pool with high %b (we don't) or if we had some sort of COW related issue; such as being <15% free space or so.  In this case, we are less than half full of a 108TB raidz3 pool.

	latencytop shows a lot of ZFS ZIL Writer latency, but thats to be expected given what I see above.  Pool I/O with zpool iostat is normal-ish, and as I said, simple raw writes to the pool show expected performance when done locally.

	Does anyone have any ideas?

Thanks,

Joe

-- 
Joe Hetrick
perl -e 'print pack(h*,a6865647279636b604269647a616e69647f627e2e65647a0)'
BOFH Excuse: doppler effect