Hi all: I'm again working on troubleshooting what appears to be poor pvfs2 performance on my cluster. Previously, it was suspected that the issue was networking, so now I have a 10GbE (Solarflare) network solution throughout. Unfortunately, transfer speeds to individual clients max out at around 70MB/s (with the servers sending 20-30MB/s) for a single concurrent client (i.e., gigabit speeds). When I scale that to 3 clients, I see the same performance, but once I add a 4th client, the servers max out at about 70-80MB/s and my clients drop to about 52MB/s. So it seems that I can only get Gigabit speeds out of the system through and through.
What I did notice is a client running at about 70-80MB/s was using up about 50% of a core. My server, when it was serving >=3 concurrent clients was using 101-107% CPU (eg, one full core plus a little). iostat -mx2 reported about 21% utilization on my disks. I'm suspecting that pvfs2's CPU-intensive portions of the server are single-threaded despite how many clients connect, so I'm going to be limited there, is that correct? Any ideas why I can't move data any faster than 80MB/s? --Jim _______________________________________________ Pvfs2-users mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
