On Feb 15, 2010, at 11:34 PM, Ragnar Sundblad wrote: > > On 15 feb 2010, at 23.33, Bob Beverage wrote: > >>> On Wed, Feb 10, 2010 at 10:06 PM, Brian E. Imhoff >>> <beimh...@hotmail.com> wrote: >>> I've seen exactly the same thing. Basically, terrible >>> transfer rates >>> with Windows >>> and the server sitting there completely idle. >> >> I am also seeing this behaviour. It started somewhere around snv111 but I >> am not sure exactly when. I used to get 30-40MB/s transfers over cifs but >> at some point that dropped to roughly 7.5MB/s. > > Wasn't zvol changed a while ago from asynchronous to > synchronous? Could that be it?
Yes. > I don't understand that change at all - of course a zvol with or > without iscsi to access it should behave exactly as a (not broken) > disk, strictly obeying the protocol for write cache. cache flush etc. > Having it entirely synchronous is in many cases almost as useless > as having it asynchronous. There are two changes at work here, and OpenSolaris 2009.06 is in the middle of them -- and therefore is at the least optimal spot. You have the choice of moving to a later build, after b113, which has the proper fix. > Just as much as zfs itself should demands this from it's disks, as it > does, I believe it should provide this itself when used as storage > for others. To me it seems that the zvol+iscsi functionality seems not > ready for production and needs more work. If anyone has any better > explanation, please share it with me! The fix is in Solaris 10 10/09 and the OpenStorage software. For some reason, this fix is not available in the OpenSolaris supported bug fixes. Perhaps someone from Oracle can shed light on that (non)decision? So until next month, you will need to use an OpenSolaris dev release after b113. > I guess a good slog could help a bit, especially if you have a bursty > write load. Yes. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance http://nexenta-atlanta.eventbrite.com (March 15-17, 2010) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
