Software RAID Under Debian

[gamehead200]

Hey guys,

I've been Googling for few hours but haven't found any descriptive guides on how to setup a software RAID under Debian, specifically a JBOD array (just a bunch of disks) or Linear RAID. I've read a bit about mdadm, but really have no clue where to start...

Why do I want this? So that I can combine a bunch of hard drives into a larger virtual one. I have done it under Windows, but have no idea how to do it under Linux.

Any help would be very much appreciated.

[allen2]

Look for mdadd, mdcreate, mdrun commands.

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

[gamehead200]

This is what I've been doing:

Set up a partition on /dev/hdb, /dev/hdc, and /dev/hdd. Then, I ran:

mdadm --create --verbose /dev/md0 --level=linear --raid-devices=3 /dev/hdb1 /dev/hdc1 /dev/hdd1

And it created /dev/md0.

I ran:

cat /proc/mdstat

and it would show up in there... Then I added a file system to /dev/md0 by running:

mke2fs -j /dev/md0

and then mounted it under /files by running:

mount /dev/md0 /files

I also ran:

echo "DEVICES /dev/hdb /dev/hdc /dev/hdd" > /etc/mdadm/mdadm.conf

mdadm --brief --detail --verbose /dev/md0 >> /etc/mdadm/mdadm.conf

and added this line in /etc/fstab:

/dev/md0  /files  ext3  defaults  0  0

The, after reboot, it wouldn't exist anymore! What am I doing wrong?

[tain]

EDIT: I misread your post. Sorry.

[gamehead200]

I haven't used mdadm, but it looks like you need to add the mounted drive to your fstab. Mounting doesn't get saved to a hard config.

pico /etc/fstab

I did. Check out my last step.

Edit: Not a problem!

[gamehead200]

Success!!!!!!!! Here are my exact steps!

1. Created a partition on each drive and set the type as Linux Raid Autodetect (FD).

2. Ran the following on each partition to clear the superblock in the MD:

mdadm --zero-superblock /dev/hdb1

3. Created the array:

mdadm --create --verbose /dev/md0 --level=linear --raid-devices=3 /dev/hdb1 /dev/hdc1 /dev/hdd1

4. Gave it a filesystem:

mke2fs -j /dev/md0

5. Added the following line in /etc/fstab:

/dev/md0 /files ext3 rw,user 0 0

6. Copied the RAID configuration to the mdadm.conf file:

mdadm --detail --scan >> /etc/mdadm.conf

7. Mounted everything:

mount -a

8. Rebooted, and everything still shows up in /files!!

Filesystem		   1K-blocks	  Used Available Use% Mounted on
/dev/hda1			  9487640	406704   8598988   5% /
tmpfs					59640		 0	 59640   0% /dev/shm
/dev/md0			  44332080	 32828  42047276   1% /files

Thanks to TAiN for doing some 1337 Googling!