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Sunday, 15 July 2007
Migrating from Windows software RAID to Hardware RAID
i started a thread on the DELL community forums asking about migrating my windows 2003 software RAID setup to a hardware RAID controller, without reinstalling windows. you can
read the thread
to get the context for these documented instructions below:
success. after a marathon 7 hour session in the datacenter it finally works. however the whole thing was much too stressful for my liking!
my problems were significantly compounded by the lack of a CD drive, so i had to get my imaging software (Terabyte Unlimited 'Image') to boot via a USB drive, which was never going to be easy with a Dell BIOS etc. although to be fair it does work, once you understand that you must reboot after configuring the BIOS to recognise the USB drive, and then go into the bios again and tell it what order to boot in.
i thought it useful to document the steps i took in case anyone else is in a similar situation.
in summary, i wanted to do an in-place migration from software raid in windows 2003 to hardware raid with the dell/adaptec CERC 6 channel SATA RAID card. all without using a CD drive (trust me, get one if you ever have to do this. i tried but couldn't get the BIOS to recognise the drive).
i got a very helpful email from Terabyte support before starting the migration:
If you just have a single simple volume (once the software RAID is broke), you can remove the dynamic drive by changing the file system ID back to 7 (via BootItNG partition work/properties). If you backup while dynamic, it will just backup the whole dynamic partition sector by sector.
So what I'd personally do is:
1. break the raid, (maybe remove the secondary drive as a backup)
2. ensure it's a single simple volume that's left (I'm assuming you just have c
3. boot BootItNG, change the file system ID to 7,
4. boot back to windows (if it didn't boot, just put back the file system id to dynamic),
5. install the CERC drivers (if needed),
6. do the image, with byte-for-byte validation (slower in windows because it thrashes a bit),
7. ensure I can access the image to restore with Image For Dos or Image For Linux.
8. Configure the hardware RAID,
9. restore the image (use additional option of TA when restoring the boot partition).
windows software RAID requires dynamic disks, which are not officially reversible back to basic disks. this further complicated the process because i wanted to go back to basic disks for the RAID. you can convert back to a basic disk as described above with BootItNG, and also via the DskProbe windows support tool, instructions available from: http://www.nthelp.com/NT6/dynamic.htm. although i also read that if you use software raid, you shouldn't use this approach, so i unplugged the second drive, booted into windows and removed the mirror, and the offline disk from Windows Disk Manager. Then i changed to a basic disk via DskProbe and it did work, although DiskManager reported a single drive, which was marked offline or something very worrying like that. however the files were all there and working etc.
i followed the instructions above, although i did install the RAID card before changing any drivers or removing the software RAID, and i got windows to load up the drivers for it, so it would work automatically once booting from the RAID controller. this was one less problem in the equation and i was keen to get it out of the way as early in the process as possible.
to get Image For Dos to boot off USB, i used the bundled 'makedisk' utility without any init strings. I configured the BIOS to emulate a USB drive as a hard drive, floppy did not work. Then rebooted and changed the boot sequence so that the USB drive came first.
the disk image (of the 'active' drive, the other was still unplugged) took about 30 minutes with byte-for-byte validation, ~25Gb of data, copying to an external USB drive, using ImageForDos. i had to change the keyboard to a PS2 connection because in my first attempt the program locked out the keyboard after identifying the USB drive.
then i verified that i could access the image with the restore option. and went ahead with setting up a RAID mirror in the CERC configuration utility. plugged in both drives into ports 4 and 5. incidentally i needed a longer SATA cable for drive0 because it only had a 4inch cable and the RAID plugs on the card are miles away from the drive bays. The cable for the other drive fit with a stretch into the last port on the card.
so i did a reboot, pressed Ctrl-A etc. initialise the 2 drives. set up a RAID 1 mirror as per the manual instructions. i used the quick-init option because i was really in a hurry to get the job done. i set high priority also. i did not 'clear' the drives, but this may have been no harm to do.
then i rebooted and loaded my restore image with ImageForDos. the 'TA' option referred to in the instructions marks the partition active and inserts a standard MBR. it took about 30 minutes again and finished successfully. i was a bit worried because the restore program asked me which drive did i want to restore to, i assumed it didn't matter and chose the second drive. my cause for concern was that i wasn't sure if the controller would do it's mirroring thing during this restore operation. my fears were doubled when i rebooted after the restore, and got a message something like "no operating system, F1 to continue, F2 to setup". at this stage i had about 5 minutes before 'visiting hours' were over in the datacentre and i would have had to take the server home for the weekend to get it ready before monday 9am, no thanks! i thought it had failed. i was about to pack up and go home when i went in to look in the bios one last time in case i missed anything. i didn't change anything, and i also inspected the RAID config via the BIOS utility, but again, didn't change anything. i tried to turn off caching as a desperate attempt to fix the boot problems, but it wouldn't accept the change for some reason. anyhow, i rebooted again, said a quiet prayer, and i couldn't believe it but windows started loading, i was never so happy to see that Windows logo appear on screen (you probably had to be there to understand, 7 hours of white noise from being surrounded by a gzillian racks, no lunch, very frustrated etc!)
now all is well with the 2 drives showing up 'optimal' in the DELL/Adaptec storage manager. i gather this means that the build/verify has already completed in the background. the URL for the storage manager is http://tinyurl.com/2nddta
i didn't want to install all that dell 'management' software that came with the RAID card.
another good thing i forgot to mention. windows disk manager now shows a healthy primary partition for C:. it doesn't say 'fault tolerant' anymore obviously because the software raid is gone and the hardware RAID is abstracted away from the windows disk manager.
hope this helps someone someday.
Sunday, 15 July 2007 00:33:07 (GMT Daylight Time, UTC+01:00)
Tuesday, 17 July 2007 22:30:06 (GMT Daylight Time, UTC+01:00)
Well done - crap like that can be *very* messy.
No doubt a long sigh of relief was let out when all was said and done ;-)
Thursday, 17 January 2008 21:12:48 (GMT Standard Time, UTC+00:00)
Nice job man. We have a similar situation with one of our servers- luckily it's old enough to still have a floppy drive :) I think I'm going to give this a shot. This def. helped me!
Tuesday, 11 December 2012 20:57:07 (GMT Standard Time, UTC+00:00)
I have to go through this also. I was afraid that it was going to come to this! Practically same setup too. I'm getting data access failures and the RAID containers are sloppy on top of being software, instead of hardware. I requested the entire work day to take the server down. Worse is that software services were installed, so I have to reinstall it and configure it. I hate reinstalling licensed software!
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