2009/8/20 Pasi Kärkkäinen <pasik@xxxxxx>: > On Thu, Aug 20, 2009 at 01:43:27PM -0700, Phill wrote: >> I'm rebuilding a RHEL 5 server used primarily for building code. >> It has perc 6i controller and I'm installing 6 15K sas drives. >> The plan is to setup a raid 10 configuration for improved performance. >> Does anyone know if I can significantly increase or degrade my performance >> by selecting a larger stripe size? The default is 64k and I have read in a >> performance report that a 512k size may be more desirable for Linux systems. >> Thanks for any replies. > > Well.. if you do large sequential reads/writes then big stripe size will > help, but if you do small random-io then large stripe size like that will be > really bad. > > It really depends on your workload. I was about to say much the same thing in closing, but actually was going to point you to this article which has different advice to Pasi's (and different to how I would expect). http://www.pcguide.com/ref/hdd/perf/raid/concepts/perfStripe-c.html It actually says that a large stripe size might be better for random transactions on lots of small files (as I would expect from compiling code), because it means you can read a whole small file from each disk in the array - so in your case you'd be able to read 6 files at once (1 from each stripe (3) multiplied by 2 (for the mirrored copies)). If you had a small stripe size, you'd increase the chance that your small file would be split across multiple disks - so you might require more than one disk per file and you wouldn't get 6 concurrent accesses - in your case it might involve up to three drives. A small number of requests for large files might benefit from small stripe sizes, because it would increase the chance that reading your large file involved reads from multiple disks - so you'd get higher throughput. As always, "large" and "small" file sizes are subjective terms and there is no substitute for benchmarking your own particular case - and this is a hotly contested subject among Storage gurus! -- Sam -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
