On Jun 12, 2008 12:42 -0700, Cliff White wrote: > Jakob Goldbach wrote: > >> I rather think of increasing lru_size only on few login nodes where > >> user access file system interactively. > > > > I run with 20k on a few-node cluster without problems. I also increased > > max_dirty_mb. Both improved small I/O. > > Basically, you want the total ( lru_size summed for all clients ) to > be less than ~500k. If you stay below that limit, should have no issues.
Exceeding this limit isn't necessarily going to cause problems either, it is really a function of your RAM size on each server. TACC Ranger has 64k cores, so it would have a maximum of 64000 * 100 = 6.4M locks on each MDT/OST (16GB RAM or so?) with the default 100 locks/core on clients. With multiple OSTs/OSS this number would increase correspondingly. > From a conversation a few years ago: > > " > If this is going to be a compile client instead of a compute client, the > standard is to increase the MDC LRU size to 5000, and the OSC LRU size > to 2000. > If they don't have thousands of clients this could be done on a large > number of clients if this test represents their normal workload (aim for > LRU * clients <= 500k should be safe)." Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
