You will find that async jounral commits don't help O_DIRECT I/O though. So, maybe you should think about using both.
Thanks, -Cory On 02/13/2011 06:04 PM, Oleg Drokin wrote: > Hello! > > On Feb 13, 2011, at 6:54 PM, Samuel Aparicio wrote: > >> We are planning OSS failover pairs for a lustre deployment, the question of >> external journals comes up. >> testing showed that for our applications having an external journal for the >> OSTs provides a worthwhile increase in performance. >> >> For a failover pair this presumably means that the OST journals should have >> to reside on an external storage target that each OSSs pair can see? > > Yes, basically you need two LUNs visible on both nodes per OST. One for the > data and one for the journal. > >> Or would the MDS journal take over in the case of an OSS switchover? > > MDS journal is just for the MDS, it has nothing to do with OSTs. > > Also you might want try async journal commits (+ make your journals big) to > see if that improves your performance in a similar way to an external journal. > > Bye, > Oleg > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
