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Configure RAID 1
2016/01/27 |
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Configure RAID 1 to add 2 new HDDs on a server.
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| [1] | This example is based on the environment below. The new HDD sdb and sdc are newly added on it and configure RAID 1. |
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root@dlp:~# df -h Filesystem Size Used Avail Use% Mounted on udev 2.0G 4.0K 2.0G 1% /dev tmpfs 396M 372K 395M 1% /run /dev/mapper/tmp--vg-root 26G 1.9G 23G 8% / none 4.0K 0 4.0K 0% /sys/fs/cgroup none 5.0M 0 5.0M 0% /run/lock none 2.0G 0 2.0G 0% /run/shm none 100M 0 100M 0% /run/user /dev/vda1 236M 97M 127M 44% /boot |
| [2] | Create a partition on new HDD and set RAID flag. |
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root@dlp:~# parted --script /dev/sdb "mklabel gpt" root@dlp:~# parted --script /dev/sdc "mklabel gpt" root@dlp:~# parted --script /dev/sdb "mkpart primary 0% 100%" root@dlp:~# parted --script /dev/sdc "mkpart primary 0% 100%" root@dlp:~# parted --script /dev/sdb "set 1 raid on" root@dlp:~# parted --script /dev/sdc "set 1 raid on"
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| [3] | Configure RAID 1. |
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root@dlp:~# mdadm --create /dev/md0 --level=raid1 --raid-devices=2 /dev/sdb1 /dev/sdc1
mdadm: Note: this array has metadata at the start and
may not be suitable as a boot device. If you plan to
store '/boot' on this device please ensure that
your boot-loader understands md/v1.x metadata, or use
--metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
# show status root@dlp:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[1] sdb1[0]
20952960 blocks super 1.2 [2/2] [UU]
[=====>...............] resync = 25.0% (5238272/20952960) finish=2.1min speed=119051K/sec
unused devices: <none>
# after few hours later, status turns like follows if syncing finished root@dlp:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[1] sdb1[0]
20952960 blocks super 1.2 [2/2] [UU]
unused devices: <none>
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| [4] | For example, if a member HDD in RAID array would be failure, re-configure RAID 1 like follows. |
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# the status is like follows in failure root@dlp:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[1] sdb1[0]
20952960 blocks super 1.2 [2/1] [U_]
unused devices: <none>
# after swapping new disk, re-configure like follows root@dlp:~# mdadm --manage /dev/md0 --add /dev/sdc1
mdadm: added /dev/sdc1
root@dlp:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[1] sdb1[0]
20952960 blocks super 1.2 [2/2] [UU]
[=====>...............] resync = 25.0% (5238272/20952960) finish=2.1min speed=119051K/sec
unused devices: <none>
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