On 9/23/14 7:46 PM, Helmut Tessarek wrote: > The information provided in the FAQ and on several web sites is not really > useful regarding RAID1. > > According to the FAQ (entry 35): > The correct options to format a RAID1 (2 disks) with 64k chunk size is: > mkfs.xfs -d su=64k -d sw=1 /dev/mapper/data I don't see that text in the faq... where is it? I see: > So if your RAID controller has a stripe size of 64KB, and you have a RAID-6 with 8 disks, use > > su = 64k > sw = 6 (RAID-6 of 8 disks has 6 data disks) but! your raid doesn't have a 64k stripe, so that doesn't apply. > But it also states that it would be automatically detected and used correctly, > yet > mkfs.xfs /dev/mapper/data > yields a different result: > > [root@atvie01s ~]# mkfs.xfs -f /dev/mapper/data > > meta-data=/dev/mapper/data isize=256 agcount=4, > agsize=244173876 blks > = sectsz=4096 attr=2, projid32bit=1 > = crc=0 finobt=0 > data = bsize=4096 blocks=976695504, imaxpct=5 > = sunit=0 swidth=0 blks no geometry because md0 raid1 doesn't export any stripe geometry. > Formel 1: > > [root@atvie01s ~]# mkfs.xfs -f -d su=64k -d sw=1 /dev/mapper/data > > meta-data=/dev/mapper/data isize=256 agcount=32, > agsize=30521728 blks > = sectsz=4096 attr=2, projid32bit=1 > = crc=0 finobt=0 > data = bsize=4096 blocks=976695296, imaxpct=5 > = sunit=16 swidth=16 blks You specified it, so mkfs obeyed. > naming =version 2 bsize=4096 ascii-ci=0 ftype=0 > log =internal log bsize=4096 blocks=476902, version=2 > = sectsz=4096 sunit=1 blks, lazy-count=1 > realtime =none extsz=4096 blocks=0, rtextents=0 > > > Another inconsistency is that RAID1 doesn't use striping, so the chunk size > should be irrelevant in the first place. agreed - but I don't see anything in the faq about raid1 stripes. Am I missing something? > So what is ultimately the correct way to format a RAID1? for software md raid over individual disks, bare mkfs should do the right thing. -Eric _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
