topic Re: Pulling a drive out of an array in Disk Enclosures

Pulling a drive out of an array

Brian Long — Wed, 11 Dec 2002 16:05:45 GMT

Compaq DL380 / 4 drives / 18GB, 18GB, 18GB, 72GB

Currently the 3 18GB's are in 1 array.
All drives are at RAID 0 in that array (Migrated from RAID 5 so there is 18GB of unused space.
There are 2 logical drives in the array.
Logical Drive 1 is 18GB and consists of the NT OS.
Logical Drive 2 is 18GB an consists of nothing. (Unpartitioned in NT)
And of course, the 18GB of space not allocated in the array.

Basically, using the Compaq Array Util, I need to remove the 3rd 18GB drive from the array and make the entire array mirrored (RAID 1). How do I do this and guarantee that data is not lost. I'm not 100% sure that using the util to just remove the 3rd drive from the array will not screw up my OS.

Re: Pulling a drive out of an array

Janine Bertolo — Wed, 11 Dec 2002 17:32:36 GMT

Hello;

With each drive in RAID0, there is no problem removing the third unpartitioned drive.

Of course, it's always a good idea to have a recent backup handy if something unforseen happens.

At this point the OS doesn't even acknowledge that third drive. Removing it shouldn't be a problem.

Sincerely,

Janine Bertolo

Re: Pulling a drive out of an array

Brian Long — Wed, 11 Dec 2002 17:40:31 GMT

From my understanding... and as explained in the link below, data is still striped across all 3 drives.

http://www.pcguide.com/ref/hdd/perf/raid/levels/singleLevel0-c.html

Re: Pulling a drive out of an array

Janine Bertolo — Wed, 11 Dec 2002 19:14:35 GMT

My apologies for not being clearer. And thanks to Brian for pointing that out.

I presumed you have three arrays off the controller - A, B, and C - each one in RAID0.

If this is the case you can remove the last one.

If you have RAID0 striped across all three drives, then you cannot remove one without affecting the others.

Janine

Re: Pulling a drive out of an array

Brian Long — Wed, 11 Dec 2002 19:20:26 GMT

Nope... 1 array... 3 logical drives within the array.... So I assume the 1 array is striped across all 3 drives.

Re: Pulling a drive out of an array

Janine Bertolo — Wed, 11 Dec 2002 21:40:35 GMT

Hi Brian;

Yes, unfortunately, in that configuration you cannot remove a hard drive without affecting the rest of the logical drives in the array.

If your aim is to remove one physical hard drive for use elsewhere, you can only accomplish that by destroying the array, reinstalling the OS and restoring any other data from backup.

Sincerely,

Janine Bertolo

Re: Pulling a drive out of an array

Donald Kok — Thu, 12 Dec 2002 10:58:58 GMT

Hi Brian,

Raid 0 (striping) puts the data blocks 1 by one on different drives:

disk 1: block 1,4,7,10....
disk 2: block 2,5,8,11...
disk 3: block 3,6,9,12....

The logical drives you have are spread across the disks.
So imagine what happens when you remove one disk. No data is available anymore. Since the NT-OS is on it, you can not just move the data temporaly.

So in your case you should install NT again without the 18GB disk(s).

Goodluck
Donald