How to remove the dead disk from a windows mirror without killing volume!


I've got a 2008 server with mirrored 500g drives.  I want to physically remove one of the disks, leaving me with a simple volume of 500gigs without losing any data.

Step one, to make sure the correct disk gets removed, I physically remove the disk I want to be gone.  That shows me a "Failed Redundancy" status in Disk Manager, and shows a missing dynamic disk, and my data is still live.  This is good, however now I need to clean up disk manager...

I can't remove the dynamic disk with the mirror still "active", so I break the mirror (See RemoveMirror.jpg)Screenshot of removing mirror , so I remove the mirror.

Unfortunately, this leaves me with apparently TWO simple volumes with the same name, but just that one of them is on a missing disk:  (See DeleteVolume.jpg) Screenshot of delting the volume.

The problem is, when I delete the volume by right-clicking on the volume on the MISSING disk, it deletes BOTH COPIES of the volume, which kills my data on the good disk,  I can't remove the disk [from the Dynamic disk database] without remioving the volume, so it looks like I'm stuck here..

Does anyone have any explanation of what I'm doing wrong?!  As I'm writing this, I'm thinking perhaps if I change the volume label on the one I want to keep, at least temporarily, that will let it differentiate between the two disks, and only delete the one volume..  Perhaps that will work, and I'll try it as soon as I can finish the remirror on my test box, but if anyone has another suggestion, I'd love to hear it!

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Gerwin Jansen, EE MVEConnect With a Mentor Topic Advisor Commented:
I understand that your situation and 'no downtime' - thanks for the explanation :)

I've found you some more (perhaps usable) details about the 'break disk' command here.

break disk
Applies to dynamic disks only. Breaks the mirrored volume with focus into two simple volumes. One simple volume retains the drive letter and any mount points of the mirrored volume, while the other simple volume receives the focus so you can assign it a drive letter.

By default, the contents of both halves of the mirror are retained. Each half becomes a simple volume. By using the nokeep parameter, you retain only one half of the mirror as a simple volume, while the other half is deleted and converted to free space. Neither volume receives the focus.
Gerwin Jansen, EE MVETopic Advisor Commented:
Hi, the volume you are trying to remove is made up of 2 physical (mirrored) disks. That volume has 1 name: ProdTestEVData1 in your case. Trying to remove 1 will remove them both because they are the same volume.

Why are you doing this btw? Do you want to use 1 500G disk for another purpose? You may want to break the mirror first, end up with 2 simple volumes and then remove 1 physical disk / volume. Procedure how to do this is here.

To make sure you don't loose any data (there is always some risk) backup your important data first.
noxchoGlobal Support CoordinatorCommented:
Delete missing fantom disk. Thats all you need to do.
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The "Why" to this is kind of crazy.. but since you asked..  :-)   The machine is actually a VMWare virtual under ESXi 4.1...  We have a 500g LUN from the SAN attached as an RDM volume.  Our backup team wants to do flash backups of a VMFS partition and wants us to get off of the RDM...  BUT we have 45 of them to do, and can't accept downtime, so we're going to attach VMFS volumes, mirror the RDMs to them, and then remove the RDMs.  The underlying LUNs (whether VMFS or RDM) are already part of a RAID set, so redundancy isn't a concern here..  SO.. the situation is more complex than I let on, but that shouldn't change the fundamental of the question.  The screenshots are of a limited test environment I'm working out the procedure on.

The situation in the KB article isn't EXACTLY the same, since it talks of boot volumes, however the procedure seems like it should be the same.  It's a shame I can't apparently do this in the GUI (making instructions for others!!) but if this works, then so be it..

I am a little skeptical though, since even my broken mirror in the screenshot above turned into simple volumes - The problem didn't happen 'till I tried to REMOVE one of those simple volumes, and Windows just decided to delete BOTH of them, because of their identical name...

@noxcho:  I am pretty sure I either tried that, and it couldn't delete a disk while there was a volume on the disk (ie: it made me delete the volume first, which put me into this same situation), or the delete disk command did actually delete the volume automatically and put me back into the situation.

I'll try again, just to make sure though...  I know that was my first intent though - Just delete the missing disk...  (That's what I'd USUALLY do if there was a disk permanently removed!)

@noxcho:  I tried again..  I dont get the option to remove the missing disk while there's a volume defined on it..  Here's what a right-click on the disk object shows:
 Cant Delete missing disk
By the way - I tried to "Reactivate" it, even though that makes no sense...  It didn't change anything.  
noxchoConnect With a Mentor Global Support CoordinatorCommented:
That's correct. Right click on the volume on disk 7 and select Break Mirror or remove Mirror. This will unbound this ghost dynamic drive. Then the Delete/remove missing dynamic disk should become available.
172pilotSteveAuthor Commented:
Sorry for being away for a while, and thanks to both of you for your help..  Both of you were helpful so I am going to try to split the points..  I've never been on "this side' of the points before, so forgive me if I screw it up..

ANYWAY..  The answer is DONT DO IT..  Removing the hard drive before the mirror was broken was a no-no..  In my further tests, removing  the mirror from the drive before removing the drive physically is the way to go..  Works great.. just have to make sure to remove the right drive.

Thanks for your help!
172pilotSteveAuthor Commented:
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