On Mon, Dec 19, 2011 at 11:58:57AM +0000, Jan-Aage Frydenbø-Bruvoll wrote: > > 2011/12/19 Hung-Sheng Tsao (laoTsao) <laot...@gmail.com>: > > did you run a scrub? > > Yes, as part of the previous drive failure. Nothing reported there. > > Now, interestingly - I deleted two of the oldest snapshots yesterday, > and guess what - the performance went back to normal for a while. Now > it is severely dropping again - after a good while on 1.5-2GB/s I am > again seeing write performance in the 1-10MB/s range.
That behavior is a symptom of fragmentation. Writes slow down dramatically when there are no contiguous blocks available. Deleting a snapshot provides some of these, but only temporarily. -- -Gary Mills- -refurb- -Winnipeg, Manitoba, Canada- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
