On Sunday 11 December 2005 17:32, Joel Palmius wrote: > On Sun, 11 Dec 2005, Blaisorblade wrote: > > Also, the iowait is on the host or on the guest? I fear on the host, but > > I'd hope not.
> No, the wait was on the guest. The guest could have 100% wait while the > host only had a few percent, leading me to think that stuff simply got > queued up somewhere and running in endless loops while waiting. Tried disabling the Anticipatory Scheduler on the host or on the guest? It's purpose is to defer reads and writes for a few milliseconds, since if it accepted a new op requiring a seek it would waste even more. Doing that twice in the request processing stack is not a good idea; probably using CFQ on the host will avoid some > Personally I've just decided to run without synchronization I had even forgot about synchronization... Yep, the process will wait until the data has gone on the disk. Ok, seems that it's logical things go slower when write caching is totally disabled. > and do good > backups instead. I'll let you know if I find this was a bad idea, these > ubds are going up in a production environment soon. :-) Test comparing ext3 and reiserfs for what I said, probably that's a good idea. Also, possibly using XFS to host the backing files could help a bit (as I said about that OLS paper, don't know if you read that). -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
