Hi,
xfs is supposed to detect the layout of a md-RAID devices when creating the file system, but it doesn´t seem to do that:
# cat /proc/mdstat Personalities : [raid1] md10 : active raid1 sde[1] sdd[0] 499976512 blocks super 1.2 [2/2] [UU] bitmap: 0/4 pages [0KB], 65536KB chunk
# mkfs.xfs /dev/md10p2 meta-data=/dev/md10p2 isize=512 agcount=4, agsize=30199892 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=120799568, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=58984, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0
# mkfs.xfs -f -d su=64m,sw=2 /dev/md10p2 meta-data=/dev/md10p2 isize=512 agcount=16, agsize=7553024 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=120799568, imaxpct=25 = sunit=16384 swidth=32768 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=58984, version=2 = sectsz=512 sunit=8 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0
The 64MB chunk size was picked my mdadm automatically. The device is made from two disks, and xfs either doesn´t figure that out, or it decided to ignore the layout of the underlying RAID.
Am I doing something wrong here, or is xfs in Centos somehow different? Do, or must, we always specify the apporpriate values for su and sw or did xfs ignore them because what it picked is better?