Создание и расширение программного raid5 и xfs

Создадим "диски"

amadis:~# dd if=/dev/zero of=img3 bs=1M count=100
amadis:~# dd if=/dev/zero of=img4 bs=1M count=100
amadis:~# dd if=/dev/zero of=img5 bs=1M count=100
amadis:~# losetup /dev/loop3 img3
amadis:~# losetup /dev/loop4 img4
amadis:~# losetup /dev/loop5 img5

amadis:~# mdadm --create /dev/md3 --level=5 -n 2 /dev/loop3 /dev/loop4
mdadm: array /dev/md3 started.

amadis:~# cat /proc/mdstat
md3 : active (auto-read-only) raid5 loop4[2](S) loop3[0]
102336 blocks level 5, 64k chunk, algorithm 2 [2/1] [U_]

amadis:~# mkfs.xfs /dev/md3

amadis:~# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 loop4[1] loop3[0]
102336 blocks level 5, 64k chunk, algorithm 2 [2/2] [UU]

Добавим третий диск в массив

amadis:~# mdadm /dev/md3 -a /dev/loop5
mdadm: added /dev/loop5

amadis:~# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 loop5[2](S) loop4[1] loop3[0]
102336 blocks level 5, 64k chunk, algorithm 2 [2/2] [UU]

amadis:~# mdadm --grow /dev/md3 -n 3
mdadm: Need to backup 128K of critical section..
mdadm: ... critical section passed.

Примечание: расширение raid6 работает только на ядре 2.6.21 и выше

amadis:~# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 loop5[2] loop4[1] loop3[0]
204672 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

amadis:~# mount /dev/md3 /mnt/
amadis:~# mount
/dev/md3 on /mnt type xfs (rw)

amadis:~# df -h
/dev/md3 95M 4,3M 90M 5% /mnt

Расширим ФС

amadis:~# xfs_growfs /dev/md3
data blocks changed from 25536 to 51168

amadis:~# df -h
/dev/md3 195M 4,5M 190M 3% /mnt

И добавим 4й диск на ходу

amadis:~# dd if=/dev/zero of=img6 bs=1M count=100

amadis:~# losetup -a
/dev/loop3: [0901]:16171160 (img3)
/dev/loop4: [0901]:16171161 (img4)
/dev/loop5: [0901]:16171162 (img5)

amadis:~# losetup /dev/loop6 img6

amadis:~# mdadm /dev/md3 -a /dev/loop6
mdadm: added /dev/loop6

amadis:~# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 loop6[3](S) loop5[2] loop4[1] loop3[0]
204672 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

amadis:~# mdadm --grow /dev/md3 -n 4
mdadm: Need to backup 384K of critical section..
mdadm: ... critical section passed.

amadis:~# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md3 : active raid5 loop6[3] loop5[2] loop4[1] loop3[0]
307008 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

amadis:~# df -h
/dev/md3 195M 4,5M 190M 3% /mnt

amadis:~# xfs_growfs /dev/md3
data blocks changed from 51168 to 76752

amadis:~# df -h
/dev/md3 295M 4,6M 290M 2% /mnt