Ivan Voras wrote: > Barkley Vowk wrote: > > >> It looks like he created a 32bit disk label. He needs to use either the >> raw device, or gpt partitions I think. >> >> Ie. /dev/mdid1 or /dev/mdid1p1 instead of /dev/mdid1s1 >> > > You're right :) > I didn't think of checking that - a wrong assumption at my part. >
If you are using partitions on a RAID device, you have to make sure you don't end up with a stripe misalignment. If there is misalignment then you end up requiring 2 I/O requests whereas otherwise 1 I/O request would suffice. Naturally this decreases IO performance (less IOps). To avoid a misalignment you have two options: - not using partitions, but using the raw device like Barkley said - use partitions (GPT or normal) and create one large partition, which starts at offset 1MiB (not MB!) thus 1024*1024 bytes. Note that you probably need to convert this to sectors (512 bytes). If you do option 2 right, then the partition will start at precisely the start of a new stripe block - thus there is no misalignment. You can use offsets like 64KiB and 128KiB but i prefer to use 1MiB since that will work with all stripesizes (up to 1MiB, which is rarely used). Merry christmas to all. :) Regards, Veronica _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hardware To unsubscribe, send any mail to "[EMAIL PROTECTED]"
