On 6/22/06, Bill Moore <[EMAIL PROTECTED]> wrote:
Hey Joe. We're working on some ZFS changes in this area, and if you could run an experiment for us, that would be great. Just do this:echo 'zil_disable/W1' | mdb -kw We're working on some fixes to the ZIL so it won't be a bottleneck when fsyncs come around. The above command will let us know what kind of improvement is on the table. After our fixes you could get from 30-80% of that improvement, but this would be a good data point. This change makes ZFS ignore the iSCSI/NFS fsync requests, but we still push out a txg every 5 seconds. So at most, your disk will be 5 seconds out of date compared to what it should be. It's a pretty small window, but it all depends on your appetite for such windows. :) After running the above command, you'll need to unmount/mount the filesystem in order for the change to take effect. If you don't have time, no big deal. --Bill On Thu, Jun 22, 2006 at 04:22:22PM -0700, Joe Little wrote: > On 6/22/06, Jeff Bonwick <[EMAIL PROTECTED]> wrote: > >> a test against the same iscsi targets using linux and XFS and the > >> NFS server implementation there gave me 1.25MB/sec writes. I was about > >> to throw in the towel and deem ZFS/NFS has unusable until B41 came > >> along and at least gave me 1.25MB/sec. > > > >That's still super slow -- is this over a 10Mb link or something? > > > >Jeff > > > > > > Nope, gig-e link (single e1000g, or aggregate, doesn't matter) to the > iscsi target, and single gig-e link (nge) to the NFS clients, who are > gig-e. Sun Ultra20 or AMD Quad Opteron, again with no difference. > > Again, the issue is the multiple fsyncs that NFS requires, and likely > the serialization of those iscsi requests. Apparently, there is a > basic latency in iscsi that one could improve upon with FC, but we are > definitely in the all ethernet/iscsi camp for multi-building storage > pool growth and don't have interest in a FC-based SAN. > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Well, following Bill's advice and the previous note on disabling zil, I ran my test on a B38 opteron initiator and if you do a time on the copy from the client, 6250 8k files transfer at 6MB/sec now. If you watch the entire commit on the backend using "zpool iostat 1" I see that it takes a few more seconds, and the actual rate there is 4MB/sec. Beats my best of 1.25MB/sec, and this is not B41. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
