On Tue, Oct 26, 2004 at 04:52:12PM -0500, Matt Mitchell wrote: > Just seeking some opinions here... > > I have observed some really poor performance in GFS when dealing with > large numbers of small files. It seems to be designed to scale well > with respect to throughput, at the apparent expense of metadata and > directory operations, which are really slow. For example, in a > directory with 100,000 4k files (roughly) a simple 'ls -l' with lock_dlm > took over three hours to complete on our test setup with no contention > (and only one machine had the disk mounted at all). (Using Debian > packages dated 16 September 2004.) Lots of small files can certainly expose some of the performance limitations of gfs. "Hours" sounds very odd, though, so I ran a couple sanity tests on my own test hardware. One node mounted with lock_dlm, the directory has 100,000 4k files, running "time ls -l | wc -l". - dual P3 700 MHz, 256 MB, some old FC disks in a JBOD 5 min 30 sec - P4 2.4 GHz, 512 MB, iscsi to a netapp 2 min 30 sec Having more nodes mounted didn't change this. (Four nodes of the first kind all running this at the same time averaged about 17 minutes each.) -- Dave Teigland <teigland@xxxxxxxxxx>
