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RAID-1OnUbuntuServerHowToSetupRAID1

Setup RAID 1 on UBUNTU

• 1. We need two identical disks.
• 2. Boot with CD -both disks should be found by the ubuntu installer CD.
• 3. Remove all partitions
• 4. Create partitions for both disks of same size and the partition type should be physical volume for RAID and not ext3. Later on we will assign the partition type.
• 5. Make sure that your /boot or the first partition have boot flag on on both disk, this is needed for the computer to boot.
• 6. One done setting up the partition go to --> "Configure software RAID" and then save the settings, you will see the picture with raid 1 partitionss.

Create new MD Devices

• If there are three partitions created by you on both disk, then create three (3) MD (multi disk) devices, which needs to be configured as RAID 1
• select the physical disk partitions to be included in the RAID-1 set.

   Disk 1 - /boot (sda1) ,   swap (sda2),     / (sda3)   ---This is DISK 1
                       |              |                |
    Disk 2 - /boot (sdb1) ,   swap (sdb2),    / (sdb3)    ---This is DISK 2 
                       |              |                |
              md0            md1               md2

The picture will be like this...

   md0 = sda1+sbd1   ---  boot

   md1 = sda2+sdb2   ---  swap 

   md2 = sda3+sdb3.  ----  /

select the filesystems and mount points for each MD device.

   md0 = ext3  /boot   

   md1 = swap  

   md3 = /  rest of the disk

• mdadm - manage MD devices aka Linux Software Raid.

RAID devices are virtual devices created from two or more real block devices. This allows multiple devices (typically disk drives or partitions there-of) to be combined into a single device to hold (for example) a single filesystem. Some RAID levels include redundancy and so can survive some degree of device failure.

Linux Software RAID devices are implemented through the md (Multiple Devices) device driver.

Currently, Linux supports LINEAR md devices, RAID0 (striping), RAID1 (mirroring), RAID4, RAID5, RAID6, RAID10, MULTIPATH, and FAULTY.

MULTIPATH is not a Software RAID mechanism, but does involve multiple devices. For MULTIPATH each device is a path to one common physical storage device.

Check man page here

The above depends on how you select the partition. If you select / as 20 gb, swap as 1 gb and rest as /home the above scheme will differ.

How to check the file system after boot

   1. check /etc/fstab

   2. Use df -h 

   3. check /proc/mdstat