On Thu, 2011-11-03 at 13:14 -0400, Christoph Hellwig wrote: > On Thu, Nov 03, 2011 at 12:29:58PM -0400, Krzysztof Adamski wrote: > > Hi All, > > > > I'm about to create a XFS file system on a MD RAID6 made up of 12 3T > > drives. > > > > This is the command line that I was planning to use: > > > > -s size=4096 > > using a sector size larger than the actual disk sector size might risk > data loss, as the log code expects sector sized writes to be atomic. > > If you have a real 4k logical sector disk it should be picked up > automatically with the kernel topology support. We don't quite do the > right thing for 512 byte logical / 4k physical disks, in which case > you might need this line. The drives I'm using are Hitachi H3IK30003272SW (0S03208) 3TB, I belive they are the 512 byte logical / 4k physical disks. > > = sunit=128 swidth=1280 blks > > In general you're better off with a 32k stripe unit / chunk size, > than the extremly large default of 512k. I'll compare a simple dd benchmark of the raw md device with 32k and 512k and report back. The resync takes over 23 hours :-( Thanks for the info. K -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
