The 512K stripe size should be fine for Lustre, and 128KB per disk is enough to get good performance from the underlying hard drive.
I don't know anything about the E18s beyond what you've posted, so I can't guess which configuration is more optimal, so I would suggest you create the RAID arrays, format the LUNs for Lustre, and run the Lustre iokit and see how the various configurations perform (3 * 4+2, 2 * 8+1, 2 * 7+2). Then please post results (with mkfs, etc command lines) here so others can benefit from your experiments and/or suggest additional tunings. Kevin On May 4, 2012, at 3:14 PM, Frank Riley wrote: >> How about doing 3 4+2 RAIDs? 12 usable disks, instead of 14 or 16, but still >> better than 8 with RAID1. Doing 4*128KB, resulting in 2 full-stripe writes >> for >> each 1MB IO is not that bad. > > Yes, of course. I had thought of this option earlier but forgot to include > it. Thanks for reminding me. So using a stripe width of 512K will not harm > performance that much? Note also that the E18s have two active/active > controllers in them so that means one controller will be handling I/O > requests for 2 arrays, which will reduce performance somewhat. Would this > affect your decision between 3 4+2 (512K) or 2 7+2 (896K)? > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss Confidentiality Notice: This e-mail message, its contents and any attachments to it are confidential to the intended recipient, and may contain information that is privileged and/or exempt from disclosure under applicable law. If you are not the intended recipient, please immediately notify the sender and destroy the original e-mail message and any attachments (and any copies that may have been made) from your system or otherwise. Any unauthorized use, copying, disclosure or distribution of this information is strictly prohibited. Email addresses that end with a ?-c? identify the sender as a Fusion-io contractor. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
