On Fri, 23 Mar 2007, Peter Rabbitson wrote: > dean gaudet wrote: > > On Thu, 22 Mar 2007, Peter Rabbitson wrote: > > > > > dean gaudet wrote: > > > > On Thu, 22 Mar 2007, Peter Rabbitson wrote: > > > > > > > > > Hi, > > > > > How does one determine the XFS sunit and swidth sizes for a software > > > > > raid10 > > > > > with 3 copies? > > > > mkfs.xfs uses the GET_ARRAY_INFO ioctl to get the data it needs from > > > > software raid and select an appropriate sunit/swidth... > > > > > > > > although i'm not sure i agree entirely with its choice for raid10: > > > So do I, especially as it makes no checks for the amount of copies (3 in > > > my > > > case, not 2). > > > > > > > it probably doesn't matter. > > > This was essentially my question. For an array -pf3 -c1024 I get swidth = > > > 4 * > > > sunit = 4MiB. Is it about right and does it matter at all? > > > > how many drives? > > > > Sorry. 4 drives, 3 far copies (so any 2 drives can fail), 1M chunk. my mind continues to be blown by linux raid10. so that's like raid1 on 4 disks except the copies are offset by 1/4th of the disk? i think swidth = 4*sunit is the right config then -- 'cause a read of 4MiB will stride all 4 disks... -dean - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
