Difference between revisions of "Raid:Growing"
| Line 83: | Line 83: | ||
mdadm: ... critical section passed. | mdadm: ... critical section passed. | ||
| − | {{tip box|msg=You need to keep --raid-devices='''4''' if you want to have an array of 4 drives+1spare, However if you do not want a spare drive, you should set --raid-devices='''5'''}} | + | {{tip box|msg=You need to keep --raid-devices='''4''' if you want to have an array of 4 drives+1spare, However if you do not want a spare drive, you should set --raid-devices='''5'''. This command can be used to grow an array of raid on the spare drive, just say to mdadm that you want to use all disks connected to the computer.}} |
{{Warning box|During the raid growing step you DO not shutdown your computer, or experienced an electrical failure, these issues can let your computer in a badly status and you can loose your data}} | {{Warning box|During the raid growing step you DO not shutdown your computer, or experienced an electrical failure, these issues can let your computer in a badly status and you can loose your data}} | ||
Revision as of 18:13, 30 October 2013
Source of this page is the raid wiki
The purpose of this HOWTO is to add a new drive to an existing Raid5 with LVM, LVM is the standard installation of SME Server. Please backup your data before starting this HOWTO, or you may loose the lot.
Growing an existing Array
When new disks are added, existing raid partitions can be grown to use the new disks. After the new disk has been partitioned, the RAID array 1/4/5 may be grown. Assuming that before growing, it contains four drives in Raid5 and therefore an array of 3 drives (3*10G) and 1 spare drive(10G). See this HowTo for understanding the automatic raid construction of SME Server
This is how your array should look before changing.
[root@smeraid5 ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [raid1]
md1 : active raid1 sda1[0] sdb1[1] sdc1[2] sdd1[3]
104320 blocks [4/4] [UUUU]
md2 : active raid5 sdd2[8](S) sdc2[2] sdb2[1] sda2[0]
72644096 blocks level 5, 256k chunk, algorithm 2 [8/8] [UUU]
Partition the new drive
for example using this command to partition the new drive
sfdisk -d /dev/sda > sfdisk_sda.output sfdisk -f /dev/sde < sfdisk_sda.output
If you have errors using the sfdisk command, you can clean the drive with the dd command.
#dd if=/dev/zero of=/dev/sdX bs=512 count=1
Adding partitions
Now we need to add the first partition /dev/sde1 to /dev/md1
[root@smeraid5 ~]# mdadm --add /dev/md1 /dev/sde1 mdadm: added /dev/sde1 [root@smeraid5 ~]# mdadm --grow --raid-devices=5 /dev/md1
Here we use the option --raid-devices=5 because raid1 uses all drives. You can see how the array looks by:
[root@smeraid5 ~]# mdadm --detail /dev/md1
/dev/md1:
Version : 0.90
Creation Time : Tue Oct 29 21:04:15 2013
Raid Level : raid1
Array Size : 104320 (101.89 MiB 106.82 MB)
Used Dev Size : 104320 (101.89 MiB 106.82 MB)
Raid Devices : 5
Total Devices : 5
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Tue Oct 29 21:39:00 2013
State : clean
Active Devices : 5
Working Devices : 5
Failed Devices : 0
Spare Devices : 0
UUID : 15eb70b1:3d0293bb:f3c49d70:6fc5aa4d
Events : 0.4
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 8 33 2 active sync /dev/sdc1
3 8 49 3 active sync /dev/sdd1
4 8 65 4 active sync /dev/sde1
After that we have to do the same thing with the md2 which is a raid5 array.
[root@smeraid5 ~]# mdadm --add /dev/md2 /dev/sde2 mdadm: added /dev/sde2
[root@smeraid5 ~]# mdadm --grow --raid-devices=4 /dev/md2 mdadm: Need to backup 14336K of critical section.. mdadm: ... critical section passed.
we can take a look to the md2 array
[root@smeraid5 ~]# mdadm --detail /dev/md2
/dev/md2:
Version : 0.90
Creation Time : Tue Oct 29 21:04:28 2013
Raid Level : raid5
Array Size : 32644096 (30.28 GiB 31.39 GB)
Used Dev Size : 7377728 (7.90 GiB 9.63 GB)
Raid Devices : 4
Total Devices : 5
Preferred Minor : 2
Persistence : Superblock is persistent
Update Time : Tue Oct 29 21:39:29 2013
State : clean
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 256K
UUID : d2c26bed:b5251648:509041c5:fab64ab4
Events : 0.462
Number Major Minor RaidDevice State
0 8 2 0 active sync /dev/sda2
1 8 18 1 active sync /dev/sdb2
3 8 34 2 active sync /dev/sdd2
4 8 50 3 active sync /dev/sde2
2 8 114 - spare /dev/sdc2
LVM: Growing the PV
Once the construction is complete, we have to set the LVM to use the whole space
[root@smeraid5 ~]# pvresize /dev/md2 Physical volume "/dev/md2" changed 1 physical volume(s) resized / 0 physical volume(s) not resized
after that we can resize the LVM
[root@smeraid5 ~]# lvresize -l +100%FREE /dev/main/root Extending logical volume root to 30,25 GB Logical volume root successfully resized
[root@smeraid5 ~]# resize2fs /dev/main/root resize2fs 1.39 (29-May-2006) Filesystem at /dev/main/root is mounted on /; on-line resizing required Performing an on-line resize of /dev/main/root to 19726336 (4k) blocks.
You should verify that your LVM use the whole drive space with the command
[root@smeraid5 ~]# pvdisplay --- Physical volume --- PV Name /dev/md2 VG Name main PV Size 30.25 GB / not usable 8,81 MB Allocatable yes (but full) PE Size (KByte) 32768 Total PE 1533 Free PE 0 Allocated PE 1533 PV UUID a31UBW-2SN6-CXFk-qLOZ-qrsQ-BIYo-nZexXo
if you can see that you have no more FREE PE you are the king of raid. But you can see also with the command
[root@smeraid5 ~]# lvdisplay
