[CentOS] RAID 1 Post Install

Kai Schaetzl maillists at conactive.com
Tue Dec 2 17:54:45 UTC 2008

Tom Brown wrote on Tue, 02 Dec 2008 17:29:06 +0000:

> http://tldp.org/HOWTO/Software-RAID-HOWTO-5.html

unfortunately that and the mini-howto are both very much outdated. Many of 
the stuff it mentions (like mkraid, /etc/raidtab) is not part of the 
distro anymore. You use mdadm nowadays. Those parts that contain mdadm 
commands are still valid.

Does this "Silicon Image SATA controller" not include Hardware RAID by 
The basic steps for software-RAID are:
- decide about the partitions the RAID devices will be based on
- if it is used only for data you may probably want to have just one RAID 
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb
(I assume you can use sda and sdb. I always use several RAID partitions, 
so I never used the whole disk.)
put LVM on it:
  pvcreate /dev/md0
  vgcreate myvolumegroupname /dev/md0
  - creates vg myvolumegroupname on it
- start adding your logical volumes:
  lvcreate -L50G --name myname myvolumegroupname
  - adds a 50G logical volume named myname
  - format that lv:
    mkfs.ext3 /dev/myvolumegroupname/myname
- copy any data you like from the old drives
- add the mount points to fstab
- if you don't boot from the RAID partition you are done now


Kai Schätzl, Berlin, Germany
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