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Line 1: − + − + − ==Adding partitions== − {{Note box|due to a bug of kernel 2.6.18 which is the default kernel of Centos5 and SME Server 8.0, you can not grown a RAID6}}+ + − When new disks are added, existing raid partitions can be grown to use the new disks. After the new disk was partitioned, the RAID level 1/4/5 array can be grown. Assuming that before growing it contains four drives in Raid5 and therefore an array of 3 drives and 1 spare drive. See this [[http://wiki.contribs.org/Raid#Hard_Drives_.E2.80.93_Raid|HowTo]] for understanding the automatic raid construction of SME Server+ − + + + Line 16:
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no edit summary
{{WIP box}}
{{level|Advanced}}
Source of this page is the [https://raid.wiki.kernel.org/index.php/Growing raid wiki]
Source of this page is the [https://raid.wiki.kernel.org/index.php/Growing raid wiki]. This is the [http://forums.contribs.org/index.php/topic,50311.0 initial forum post] which gives the need to write the the howto
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==
{{Note box|due to a bug in kernel 2.6.18 which is the default kernel of Centos 5 and SME Server 8.0, you can not grow a RAID6}}
This is how your array looks before.
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 [[Raid#Hard_Drives_.E2.80.93_Raid|HowTo]] for understanding the automatic raid construction of SME Server
This is how your array should look before changing.
[root@smeraid5 ~]# cat /proc/mdstat
[root@smeraid5 ~]# cat /proc/mdstat
md2 : '''active raid5''' sdd2[8](S) sdc2[2] sdb2[1] sda2[0]
md2 : '''active raid5''' sdd2[8](S) sdc2[2] sdb2[1] sda2[0]
72644096 blocks level 5, 256k chunk, algorithm 2 [8/8] [UUU]
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
for example using this command to partition the new drive
sfdisk -d /dev/sda > sfdisk_sda.output
sfdisk -d /dev/sda > sfdisk_sda.output
sfdisk -f /dev/sde < sfdisk_sda.output
sfdisk -f /dev/sde < sfdisk_sda.output
If you have errors about sfdisk command, you can clean the drive with the dd command. Be aware that dd is called data-destroyer, think about which partition you type.
If you have errors using the sfdisk command, you can clean the drive with the dd command.
{{Warning box|Be aware that dd is called data-destroyer, be certaing of the partition you want zeroed.}}
#dd if=/dev/zero of=/dev/sdX bs=512 count=1
#dd if=/dev/zero of=/dev/sdX bs=512 count=1
===Adding partitions===
{{Note box|msg=The process can take many hours or even days. There is a critical section at start, which cannot be backed up. To allow recovery after unexpected power failure, an additional option <code>--backup-file=</code> can be specified. Make sure this file is on a different disk or it defeats the purpose.
mdadm --grow --raid-devices=5 --backup-file=/root/grow_md1.bak /dev/md1
mdadm --grow --raid-devices=4 --backup-file=/root/grow_md2.bak /dev/md2}}
Now we need to add the first partition /dev/sde1 to /dev/md1
Now we need to add the first partition /dev/sde1 to /dev/md1
[root@smeraid5 ~]# mdadm --grow --raid-devices='''5''' /dev/md1
[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:
{{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}}
[root@smeraid5 ~]# mdadm --detail /dev/md1
[root@smeraid5 ~]# mdadm --detail /dev/md1
/dev/md1:
/dev/md1:
Preferred Minor : 1
Preferred Minor : 1
Persistence : Superblock is persistent
Persistence : Superblock is persistent
Update Time : Tue Oct 29 21:39:00 2013
Update Time : Tue Oct 29 21:39:00 2013
State : clean
State : clean
Failed Devices : 0
Failed Devices : 0
Spare Devices : 0
Spare Devices : 0
UUID : 15eb70b1:3d0293bb:f3c49d70:6fc5aa4d
UUID : 15eb70b1:3d0293bb:f3c49d70:6fc5aa4d
Events : 0.4
Events : 0.4
Number Major Minor RaidDevice State
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
0 8 1 0 active sync /dev/sda1
After that we have to do the same thing with the md2 which is a raid5 array.
After that we have to do the same thing with the md2 which is a raid5 array.
[root@smeraid5 ~]# mdadm --add /dev/md2 /dev/sdj2
[root@smeraid5 ~]# mdadm --add /dev/md2 /dev/sde2
mdadm: added /dev/sdj2
mdadm: added /dev/sde2
[root@smeraid5 ~]# mdadm --grow --raid-devices='''4''' /dev/md2
[root@smeraid5 ~]# mdadm --grow --raid-devices='''4''' /dev/md2
mdadm: ... critical section passed.
mdadm: ... critical section passed.
{{Tip box| For md2 you have to keep --raid-devices='''4''' if you want to have an array of 4 drives+1spare, if you want no spare 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}}
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/sdc2
4 8 50 3 active sync /dev/sde2
2 8 114 - spare /dev/sdd2
===LVM: Growing the PV===
{{Note box|Once the construction is complete, we have to set the LVM to use the whole space}}
* In a root terminal, issue the following command lines
[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
{{tip box|/dev/main/root is the default name, but if you have changed this you can find it by typing the command : lvdisplay}}
[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
On Koozali SME v10 you should use xfs_growfs instead of resize2fs
[root@smev10~]# xfs_growfs /dev/main/root
meta-data=/dev/mapper/main-root isize=512 agcount=4, agsize=1854976 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=7419904, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=3623, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 7419904 to 11615232
[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
<noinclude>[[Category:Howto]][[Category:Administration:Storage]]</noinclude>