Adding physical disk to RAID-5 array (with a wrinkle)

Question

When I created this array originally, I was unaware I would not be able to expand it. I think I've found out the hard way, though. System is a PE 2850 Rack Mounted Server running Windows 2003 Server R2 Standard Edition. When I first recieved the server, I created a RAID-5 SCSI array on a PERC 4e/Di controller with three physical identical disks. I then created a second virtual disk using the leftover space that I didn't use in the first virtual disk. Now I am ready to expand the array, and I found out that it isn't possible when there is more than one virtual disk in the array. Is there any way around this limitation? I now have a fourth physical disk, but no real way to add it to the existing array. What are my options? Thanks for any help.

Mark_A_Smith · Answer

Backup -> recreate array from scratch -> Load OS -> restore.   Sorry - this is the only option with a 'sliced' array.

DELL-GaryS · Answer

Agree with Mark, and add comment that slicing the physical drives into multiple arrays, while possible, does complicate recovery from drives going offline. I would advise in the strongest terms that when you recreate the array, you make it a single array using 99% of the free space on your drives, then use partitions to make your other drive letters.   Regards, Dell-GaryS

pharmboy1234 · Answer

Believe me---lesson learned. When I created that array that way, I had zero idea what I was doing. I was learning as I went. I ended up with a useable config, as I was able to install 2003 Server on it, but I didn't do my research first and had no idea about this gotcha. :-) I will be doing it the way you suggest when I re-create the array, once I am confident in my backup I will be using to restore data. Thanks for the help.

jjaymick · Answer

Another option would be... Assuming that the drive you are adding is the same size as the other drives you could follow this process. 1. Fault 1 drive in your current Raid 5. 2. Use your new disk and the faulted disk to create a RAID 0. (should be the same size as the orig R5) 3. Use a tool like ghost or DD to move the OS partition and not expand it. (this should leave the remainder unallocated. and drive C: intact) 4 Boot to original OS on faulted R5. 5 Create a partiton in the unused space on R0 and copy data from D:  drive. (now all data should be over on the R0 and it should be bootable) 6 Test boot the R0 by changing boot-logical drive in the Raid Bios. 7 If it boots Ok and all data is there delete your original RAID sets which should make disk 0 and 1 unconfigured 8 Expand your RAID0 to a RAID 5 with the remaining unconfigured disks. the resulting config should be 1 R5 4 drives and all data there, however the space used by the partitions will not include the additional space of the 1 drive. (to include this space use the EXTPART utility to expand the last partition out to the end of the drive.   Please make sure before you try this that you have a complete verified back up of all this data and configs...  As well make sure that your RAID sets are redundant by completing a consistency check on the R5.

pharmboy1234 · Answer

Hmm, that's an interesting idea. I may end up going that route.

In fact the more I look at it, the better I like it. Only question I have is how do you purposely fault the RAID-5 Array? I mean I know it would fault if I simply removed a drive, but I don't think that's what you mean. I could take a drive offline in OMSA, but wouldn't it just start auto-rebuilding as soon as I brought it back online again? Sorry if I'm not quite clear on this.

I had planned on simply using Ghost 8 from a BartPE-Windows Boot CD (with Perc 4e/Di Drivers built in) and ghosting both drives over to two image files on an IDE drive hooked up to the server in question. Then delete and recreate the array properly, and ghost the two images back.

I know this isn't supported, but I've spoken to a few people that say they have done it with similar hardware.

Either way, thanks for the idea, and I will be sure to test my tape backup before trying anything.

Message Edited by pharmboy1234 on 05-02-2007 02:47 PM

jjaymick · Answer

If you have external storage to move the ghost images to... That would be way easier.  I was making the above post based on the hardware that you mentioned and no additional hardware.   Yes, faulting the drive is as easy as failing the drive in Open Manage or physically removing it.  If it does start to rebuild just cancel the rebuild and it will not start until you start it again.

DELL-GaryS · Answer

You might run into a gotcha or two on that.   First off if you have the Dell utility partition installed, you should create a matching partition on the RAID 0 before you move the OS to it., so the boot.ini file will not need to be messed with.   Second, with a split set of drives, you may not need to fault a drive to get the same capacity as your C:, and before faulting anything, run a consistancy check or patrol read to find and remap any media errors. Check your backup logs for any files that failed to copy, resolve any corrupted files and verify you got EVERYTHING backed up before proceeding.   You could use the O/S mirroring capability to get the O/S mirrored onto the RAID 0.   There could be more, but this is a quite technical process, with several points of risk, at worst case if it fails you go back to plan A, delete all arrays and logical drives, create a new array, and reinstall, restore.   Good luck Dell-GaryS

pharmboy1234 · Answer

Thanks Gary, I actually DO have the utility partition installed, as I used the utility CDs that came with the server to do the original install of Windows 2003 when I initially recieved the server and borked this RAID config. That's good info regardless of which path I take, as the boot.ini file would probably throw an error if I try to boot without that utility partition there.

Actually I plan to ghost each "RAID Virtual Disk" as an entire drive, which means the system image (VirtualDisk0) will include the dell utility partition. I may ghost the individual partitions to images (just in case) as well. (The IDE drive I'm planning to use for this purpose is 120GB and the system partition in question is only ~10GB, so I can afford to be a bit cautious and create images of both the entire drive and both of the individual partitions on the c: drive.)

The data drive is something I have backed up in mutiple locations including tape, CDs, and my workstation's HDD, so I'm not (terribly---Murphy, leave me alone!) worried about that data.

Alternatively I'm fairly sure I can edit the boot.ini to boot the system partition properly without the utility partition there via WindowsPE CD once I've done the restore.

Thanks for the info guys, the more I read (and I've been doing a LOT of reading about this process) the more I think I can make it through this.

Worst case I end up installing from scratch and restore data from backup tapes. I'd really rather avoid that process if at all possible, but I'm certain I can get the server back in service if worse comes to worst. I will of course be doing this on a weekend. :-)

Message Edited by pharmboy1234 on 05-02-2007 09:07 PM

pharmboy1234 · Answer

Well, I just finished the reconfiguration this afternoon. It took a while, but that was mostly the extra care I took with the data. I had a spare 160GB IDE drive which I was going to use to hold my Ghost images. I shut the server down and opened it up only to realise there were no internal IDE connectors in a PE2850 server. Duh. Plan B. I happened to have an external USB2.0 IDE HD enclosure in my car. Boot up the server, attach the enclosure with my 160GB drive via USB, drive recognised, I format it NTFS, away we go.

1. I checked my tape backup to verify it was good.

2. I ran a full backup of all my SQL databases to the spare 160GB drive.

3. I rebooted to my BartPE disk, it loaded fine, PERC drivers that I had integrated seemed to work fine, I was able to see the server's hard drives in My Computer.

4. I ran Ghost 8 and backed up Virtual Disk 0 (Contained Dell Utility Partition and the C Drive) to an image (VD0.gho), then backed up Virtual Disk 1 (the data disk containing SQL databases and other data) to an image (VD1.gho).

5. Then I backed up each partition to its own image, just to be sure. I figured I may as well, as the 160GB disk I was using had plenty of space. I had a look at the images with Ghost Explorer, all seemed to be there.

6. Rebooted to the RAID Bios, and cleared the RAID Array data. I think a few beads of sweat ran down my face as I was doing this. :-) I re-created the array as one large drive (including the 4th HD I purchased for this purpose) and initalized it.

7. Rebooted to BartPE again, started Ghost, restored the VD0.gho image and gave the C partition a bit more space while I was at it. After this finished, I ghosted the VD1.gho image back to the remaining unallocated space on the array drive.

8. At this point I started Paragon Hard Disk Manager and for some reason, converted the Data drive from a Primary to a Logical Partiton. I really don't know why I did this, but I regretted it as it took two hours, and I'm fairly certain it would have been fine left as the second primary partition on the disk. 2 hours: wasted. Oh I also made the Dell Utility partition a hidden partition. I don't think this worked correctly, as I ended up having to delete it.

9. Crossed my fingers and booted the re-imaged server. The server boots. Yay.

I had to delete the Dell Utility Partition because even though it was hidden, windows insisted upon giving it the drive letter I needed for the data partition. Not sure why this was, but I couldn't change the letter in disk management, the option wouldn't appear, so I just deleted the partition. Didn't really need it anyway. Then I had to change the data drive's drive letter to the one the utility partition had been refusing to give up, and after that and a reboot, everything worked perfectly.

I set the data drive to defragment (Ghost always leaves a ton of fragmentation on re-imaged drives) and went home.

All in all, the whole process went pretty smoothly. I can verify that Ghost 8 worked quite well with a Perc 4e/Di controller from BartPE loading the Perc 4e/Di Drivers.

Anyway, thanks for all the info above, it helped me a lot to decide how to approach this situation.

Message Edited by pharmboy1234 on 05-06-2007 07:49 PM

Message Edited by pharmboy1234 on 05-06-2007 07:51 PM

Message Edited by pharmboy1234 on 05-06-2007 07:54 PM

DELL-GaryS · Answer

If you don't format the fake Utility partition, it will not be assigned a drive letter. I use the FDISK utility from a DOS boot disk to accomplish this feat, creating the partition, but not doing anything else with it. The programmers these days assume that if you create a partition, you will always want to format it to be usable by your O/S, thay's why the need for the old school utility.   I'm glad you were able to reach your end goal, and did not need your backup.   Regards, Dell-GaryS

pharmboy1234 · Answer

I'm considering recreating the partition and somehow adding in the utility stuff again. But I almost want to leave well enough alone. Everything works, I should just be happy, no? :-)

The utility stuff isn't that important to me, I can just boot the utility CD if I ever need that stuff.

There is the unallocated ~31MB space at the beginning of the disk now, and the obsessive-compulsive in me wants to fix it, but I think I'll leave it alone for now.

DELL-GaryS · Answer

Don't go there, making the Utility partition work would require a deletion of your partitions , booting from the open manage CD, and creating the utility partition. (there cannot be any partitions on the array when creating the utility partition.)   Regards, Dell-GaryS

pharmboy1234 · Answer

Got it. Thanks.

PowerEdge HDD/SCSI/RAID

Adding physical disk to RAID-5 array (with a wrinkle)

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