Raid1 Setup

(1) Proceed with the standard CAL auto-installation. During the disk partitionin stage of the installation, select the manually edit option.

(2) Delete all partitions on both disks.

(3) Create the following partitions:

  • two 200mb partitions, one on each drive (boot flag enabled and primary partitions).
  • two partitions, one on each drive, with the remainder

of disk space (logical paritions).

All paritions should be formatted as physical raid disks.

(4) Under the software raid configuration, select create raid1 device. Follow the wizard, and selecting matching partitions:

sda1 and sdb1 as md0 sda5 and sdb5 as md1

(5) Format the available partitions as:

  • 200mb partition (ext3, mount point: /boot)
  • Remaining partition (LVM)

(6) The script will handle the volume group and logical volume creation.

If manual partitioning is required, use the following:

LVM Paritioning:

VG (volume group) Ubuntu

 /home    1GB
 /(root)  1GB
 Swap_1   3 X total system memory
 /usr     4GB
 /var     4GB
 /scratch remaining space

 * Format all partitions in the ext3 format. 

Boot Parition (ext3):

/boot 200mb 

 * Note: boot partition must be created outside of the LVM file 
system as Grub (the boot loader) will not recognize the LVM boot partition.

(7) Proceed with the auto-installation.

(8) Install grub onto the second drive:

	sudo grub-install /dev/sdb

	sudo grub:
		root (hd1,0)
		setup (hd0)
		setup (hd1)

* tab complete is helpful.

(9) To check the status of the RAID1 system:

cat /proc/mdstat

Personalities : [raid1]
md1 : active raid1 sda5[0] sdb5[1]
      244043264 blocks [2/2] [UU]

md0 : active raid1 sda1[0] sdb1[1]
      96256 blocks [2/2] [UU]

unused devices: <none>

* Note: Both raid devices, md0 and md1 
should be visible. During the initial startup,
the system will mirror the primary drive to the second drive
of the raid array. It usually takes 15-20 minutes to complete 
the file transfer---a progess indicator will can be seen when 
issuing the above command.

(10) To test the RAID1 setup, make sure that the mirroring of the files is complete. Disable the primary drive under the bios setup. On most Dell machines, select the 'F2' key at boot up and turn off the SATA 0 drive. Save the settings and restart the system. The workstation should start up with no problems. When issuing the 'cat /proc/mdstat' command, an underscore character [_U] indicates that one of the drives has been depricated or is not available. The system admin. will also be notified with an email. We can now reboot the system and re-enable the primary dirve. After rebooting, manually add the enabled primary drive to the array:

sudo mdadm /dev/md0 --add /dev/sda1 sudo mdadm /dev/md1 --add /dev/sda5

Repairing a Raid1 Setup

repairing RAID1