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gamehead200

Sep 24 2006, 10:03 PM

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

Sep 25 2006, 08:39 AM

Look for mdadd, mdcreate, mdrun commands.
http://tldp.org/HOWTO/Software-RAID-HOWTO.html

gamehead200

Sep 25 2006, 04:38 PM

This is what I've been doing:

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

CODE

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

And it created /dev/md0.

I ran:

CODE

cat /proc/mdstat

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

CODE

mke2fs -j /dev/md0

and then mounted it under /files by running:

CODE

mount /dev/md0 /files

I also ran:

CODE

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:

CODE

/dev/md0 /files ext3 defaults 0 0

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

tain

Sep 25 2006, 05:24 PM

EDIT: I misread your post. Sorry.

gamehead200

Sep 25 2006, 05:25 PM

QUOTE (TAiN @ Sep 25 2006, 07:24 PM)

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.

QUOTE

pico /etc/fstab

I did. Check out my last step.

Edit: Not a problem!

gamehead200

Sep 25 2006, 06:16 PM

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:

CODE

mdadm --zero-superblock /dev/hdb1

3. Created the array:

CODE

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

4. Gave it a filesystem:

CODE

mke2fs -j /dev/md0

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

CODE

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

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

CODE

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

7. Mounted everything:

CODE

mount -a

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

CODE

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!

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