Windows 2008 R2 Software Mirror

elemist
elemist used Ask the Experts™
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2008 R2 Server running SBS 2011 with two 1.5TB hard disks mirrored together from within Windows.

Ran fine with no problems up until a restart this evening. I restarted it remotely, so not sure if it installed updates before it shut down or not - there were some waiting.

Prior to the restart i deleted a whole bunch of files freeing up approx 45GB (was already about 50GB free).

On restart server was failing to boot of the first option in the boot menu. Usual windows has failed to start - try booting of DVD and running repaired setup.

I powered the machine off completely and restarted it. This time it blue screened on startup, then the following restart gave me the option to boot into the recovery environment. The recovery environment couldn't detect any fault with the startup, but still blue screening on startup.

Finally restarted again and selected boot from the second hive and its booted with no issues. However in disk managment the mirror is showing both drives, but with "failed redundancy"

I'm a tad confused about how/why this happened and how i'm still able to boot the second hive. The mirror has clearly been updating as the files i deleted just before the restart are not there.

Not quite sure how to proceed - i can't see anywhere the SMART status for the drives, so i'm unsure if one has failed. That said in disk management i can see both drives and the partitioning with no problems.

There's no obvious crunching or unusual noises coming from either of the drives that would lead me to believe one of them has died.

The only options i have are to remove the mirror or reactivate disk and i have these on both of the physical disks.

I'm hesitant to do anything in case it ruins the "good" mirror, but i don't want to leave it because clearly there is an issue.

I'm currently running a full backup to an external hard disk just in case!
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Backup is a good idea.

I would try rebooting normally and maybe falling back to an earlier restore point if available.

You might want to run some disk diagnostics.

If you remove the mirror the system should run fine. You just won't have redundancy.

Author

Commented:
Checked for previous restore points - but i didn't have that configured so nothing available.

Disk checks are my next point of call.

I assuming by booting from the "second hive" you basically booting off the second disk right? Is there any way of telling which disk is which without shutting the server down and unplugging one then the other?
Unplugging drives is the sure fire way of determining the boot drive. Since they are mirrors it really shouldn't matter which you bring up.

You might try uninstalling any recent updates.
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Booting from 2nd hive really sounds like Server is using an alternative boot section in the registry rather than a physical drive.

Author

Commented:
Yeah - trying to avoid a shut down until i know roughly what the issue is. I have a busy couple of weeks ahead and no time to be messing about with it, and i being its my primary mail server i can't have it offline.

I thought about the updates, but it doesn't make sense to me. Surely being a mirror what was applied to one would be applied to the other. Thus ruling out updates. In addition i did restart, not shutdown so technically updates shouldn't have installed?

Agree with the alternate boot section. But then why would the mirror show as failed redundancy. Surely the only thing that could cause this would be one of the two drives failing?
Yes the mirrors are identical and there are obviously some issues with Windows Server R2. It sounds like one hive in the registry is corrupted and it's using a backup copy to get you up and running.

Uninstalling the updates is a long shot but easier than shutdown and unplugging a drive.

It could be that the 2nd hive is just not setup to handle a mirror. You could try reactivating the mirror. If it fails it may be that the hive can't handle it. It may also ask you to reboot normally which may blue screen again.

Since it's showing "failed redundancy" your drives are not really functioning as a mirror at this point.
Maybe you have something like this going on. Check your system log for errors.

http://serverfault.com/questions/80344/windows-server-software-raid-volume-constant-failed-redundancy

noxchoIT Product Manager
Top Expert 2009

Commented:
Prior to the restart i deleted a whole bunch of files
what files exactly did you delete?

Author

Commented:
Just the ones in program files??? haha no just kidding. Wondered if anyone would pickup that phrase...

Nothing important. Just a whole bunch of tv episodes i had acquired. Was more a comment to point out that the RAID mirror was intact - otherwise the files i had deleted would still be there!
noxchoIT Product Manager
Top Expert 2009

Commented:
Interesting. And is your system now booted from single HDD? Or is it using partition from one disk as boot and partition from another disk as system?

Author

Commented:
Both drives are still connected. When i boot up i always have the option of two boot sources

Something along the lines of:

Windows 2008 R2
Windows 2008 R2 - Second Hive

It defaults to the 1st option, however when that wouldn't boot i took a chance and tried the second option and thats what is currently running.

I just have no idea which drive it is running off, or if its both still? Because the mirror is showing as failed redundancy its cleary not mirrored..
noxchoIT Product Manager
Top Expert 2009

Commented:
Windows Disk Management screenshot please.

Author

Commented:
Screenshot attached.

Cheers
Capture.PNG
noxchoIT Product Manager
Top Expert 2009

Commented:
So it is running still from a single HDD. Remove the mirror or brake the mirror. You have to do this in any case. Without mirror you will have more ways to fix the issue than with mirror.

Author

Commented:
Sorry for the delay - Flat out sorting out everyone else's issues :) Will get to it next week hopefully..
Commented:
OK so i found one of the SATA cables was faulty. Replaced it and rebuilt the array and everythings back to normal.

Author

Commented:
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