We will test the mem=12G suggestion. Before attempting the 1.8.0 client, can you confirm that a 1.8 client should work with a 1.6 server without causing any more complications?
/bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Andreas Dilger Sent: Monday, May 11, 2009 1:54 PM To: Hayes, Robert N Cc: [email protected] Subject: Re: [Lustre-discuss] (no subject) On May 11, 2009 13:35 -0700, Hayes, Robert N wrote: > While performing a single copy, single client write/read test using dd, > we find that our Nehalem clients running 2.6.18-92.1.10.el5-lustre-1.6.5.1 > write about half the speed of our Nehalem clients running > 2.6.18-53.1.13.el5_lustre.1.6.4.3 to three different lustre file systems. > This is true even though the slower clients have the same processors and > more RAM, 18GB for the slow writers and 12GB for the fast writers. Both > systems use OFED 1.3.1. All benchmarks we use perform better on the > slow-write clients and read speed from LFS is comparable across all > clients. Have you tried booting the slower-with-more-RAM clients using "mem=12G" to see if the performance gets worse with more RAM? There is a known performance bottleneck with the client-side cache in 1.6 clients, and you may be triggering this... If you have the luxury to do so, testing a 1.8.0 client's IO performance against the same filesystems would also determine if the client-side cache performance fixes therein will already solve your problems. 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
