Hi Tobias, comments below… On Dec 21, 2013, at 5:15 AM, Tobias Oetiker <[email protected]> wrote:
> I am running omnios r151008 on a recent box with 3gig SAS disks > arranged in a raidz2 pool. > > I have this 7TB filesystem where I have my zimbra server store its > backups. The backup-sets are highly redundant, so for a time I had > deduplication turned on to great effect, but as the size of the > backup-sets grew, I ran out of ram and performance on the system > became realy bad. So I turned deduplication of. Performance for > newly written data is fine again. > > The other day, I destroyed a bunch of old snapshots on this > filesysem. Thanks to background destruction this did not realy take > a long time. But now as background destruction is progressing, the > system remains very slugish when doing io on the pool where > the destruction is taking place. > > I put up some graphs and raw data on > > http://tobi.oetiker.ch/background-destruction/ > > to show the state of things. > > My Questions: > > a) would it be faster to send/receive the content of the > deduplicated filesystem to a new non deduplicated > and then destroy the entire filesystem (not the pool). > > b) is there a way to monitor progress on the background > destruction? > > c) shouldn't the smarter write throttle change > > https://github.com/illumos/illumos-gate/commit/69962b5647e4a8b9b14998733b765925381b727e > have helped with this by makeing zfs do its internal things > with a lower priority. Yes, but the default zfs_vdev_max_pending remains at 10. Once the I/Os are sent to disk, there is no priority scheduling. You should consider lowering zfs_vdev_max_pending to allow the ZIO scheduler to do a better job of rescheduling the more important I/Os. — richard > > cheers > tobi > > > -- > Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland > http://it.oetiker.ch [email protected] ++41 62 775 9902 / sb: -9900 > > > ------------------------------------------- > illumos-discuss > Archives: https://www.listbox.com/member/archive/182180/=now > RSS Feed: https://www.listbox.com/member/archive/rss/182180/21175743-23d1427b > Modify Your Subscription: https://www.listbox.com/member/?&; > Powered by Listbox: http://www.listbox.com ------------------------------------------- illumos-discuss Archives: https://www.listbox.com/member/archive/182180/=now RSS Feed: https://www.listbox.com/member/archive/rss/182180/21175430-2e6923be Modify Your Subscription: https://www.listbox.com/member/?member_id=21175430&id_secret=21175430-6a77cda4 Powered by Listbox: http://www.listbox.com
