Changes

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]

The purpose is to add a new drive to an existing Raid5 with LVM which is the standard installation of SME Server. Please backup your datas before to start this HOWTO, '''you may loose them'''.

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==

==Growing an existing Array==

{{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 grow a RAID6}}

{{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}}

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 (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

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 looks before.

This is how your array shpould look before changing.

  [root@smeraid5 ~]# cat /proc/mdstat

  [root@smeraid5 ~]# cat /proc/mdstat

  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.

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, think about which partition you type.}}

{{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

  [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 the raid1 use all drives. You can see how the array is

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

  [root@smeraid5 ~]# mdadm --detail /dev/md1

===LVM: Growing the PV===

===LVM: Growing the PV===

Once the construction is done, we have to set the LVM to use the whole space

Once the construction is complete, we have to set the LVM to use the whole space

[root@smeraid5 ~]# pvresize /dev/md2

[root@smeraid5 ~]# pvresize /dev/md2