Need to stop using software raid level 1

pshoaf · 06-05-2009, 03:56 PM

I have a RedHat ES 4 server with 2 drives sda & sdb. Each drive has 3 partitions (/boot, swap, and /). /dev/md0 is /dev/sda1 & /dev/sdb1 and /dev/md1 is /dev/sda3 and /dev/sdb3, while /dev/sda2 and /dev/sda3 are used for swap.

I need to remove the raid from /boot (/dev/md0) and revert back to a single drive. I found an earlier post from 1-17-2005 that said...

Quote:

With RAID1 its easy.

Step 1. Locate your raid configuration file under /etc/raidtab.
If you dont find one, have mdadm generate one for you.
Step 2.
Identify the child partitions that make up md0 and md1.
The SATA disks may appear as SCSI devices sda and sdb, not sure on FC3, otherwise they would be ide. (hda, hdb)

For this discussion, I will assume md0 is made of sda1 + sdb1 and md1 is sda2 + sdb2

Step 3. Modify you /etc/fstab file and replay md0 with sda1, then replace md1 with sda2.

Step 4. Cross your fingers

Step 5. Reboot, If all goes well, your should now be running on the first disk.

Good luck!

Has anyone done this? I am working with a production server and don't like step #4. Any all help is greatly appreciated.

acid_kewpie · 06-05-2009, 04:21 PM

step 4 is optional. ;-)

Seriously though, there's nothing to go wrong. Software RAID 1 is just two normal identical file systems with a RAID identifier. The worst that would happen is that after you have mounted a single partition then it no longer starts as a RAID 1, but you don't wwant that to happen anyway.

pshoaf · 06-10-2009, 09:01 AM

Well, I went in to the /etc/fstab and made the changes, abd /boot did not mount. I changed everything back and gave up. I copied the /md partitions to a new drive the booted that. I truly wish there was a way to convert from Raid Level 1 (mirroring) back to single drive no raid.