June 3, 2010

RAID Disk Configuration (mdadm.conf)

Back again with a very quick tip: RAID disk array configuration.

After few articles like:
Installing GRUB on the other disks
Replacing faulted raid drive
I'm just adding my configuration related to one of my RAID installations on a linux server.

Machine has Gentoo Linux (current portage, AMD64 arch) and a RAID system with only two SATA drives with a simple RAID1 config. Nothing more, nothing less

Quite easy config to have a virtual disk composed like this:

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/md2 4806824 997012 3809812 21% /
tmpfs 449108 0 449108 0% /lib/init/rw
udev 10240 144 10096 2% /dev
tmpfs 449108 0 449108 0% /dev/shm
/dev/md0 90195 11088 79107 13% /boot
/dev/mapper/storage-storage 306966528 82096984 224869544 27% /home

I've a boot partition (md0), a swap partition (md1), root partition (md2) and a logical volume manager (LVM) on /dev/md3

Nothing strange, nothing spectacular, every configuration is maded by hand, no fancy graphical tools involved. Config related to RAID5 installations have the same layout

Here's the array configuration file (mdadm.conf)

# scan all partitions (/proc/partitions) for MD superblocks.
DEVICE partitions

# auto-create devices
CREATE owner=root group=disk mode=0660 auto=yes

# tag arrays as belonging to the local system
# Monitoring daemon instructions
MAILFROM FileServer Administrator
MAILADDR This e-mail address is being protected from spambots. You need JavaScript enabled to view it

# MD array
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=d4eb97cf:da422dd0:36eb05f3:bbd531f4
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=a614ae3f:a9afcbfc:91f980c8:762e06bc
ARRAY /dev/md2 level=raid1 num-devices=2 UUID=19d6f845:358ff0a9:188cf822:397115dc
ARRAY /dev/md3 level=raid1 num-devices=2 UUID=24346f3b:bad36d8b:961a4a14:4eae9079

# Modified by Ben

Again, nothing strange here, hope it helps newbies or contributors interested in a RAID installation, please share your thoughts if this simple config can be better

Next step: LVM configuration sample


Hope it helps you
Glad to read your comments


Andrea (Ben) Benini