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I installed Windows 7 Ultimate on my system and it has two disk drives.

Windows 7 partitioned Disk 0 as:

  • 100MB for "System Reserved"
  • The rest for C: (incl. boot, page file, crash dump)

Now I want to mirror Disk 0 (setup Disk 1 as a mirror of Disk 0 in windows software raid).

So I change Disk 0 to a Dynamic disk and then add a mirror on Disk 1. To my surprise, it grabbed a hunk of Disk 1 and mirrored C: but it didn't mirror the 100MB System.

Well...that's no good - if Disk 0 dies, I want to be able to boot off Disk 1, put in a new disk, resync, and be back in business with a minimum of fuss.

When I click on the System Reserved partition and say "Add Mirror", it asks me to select a disk. I select Disk 1 and it gives the error "No extents were found for the plex".

Here is what my disks look like:

enter image description here

I thought maybe it was some rounding issue perhaps, but even shrinking System Reserved to 84MB still gives me the same error.

How can I have Disk 1 be a complete mirror of Disk 0 so that if Disk 0 dies, Disk 1 is ready to run?

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Did you try Google first, you are supposed to do "some" research before posting a question...encrypted.google.com/… –  Moab Nov 13 '11 at 23:36
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4 Answers 4

Add the "System Reserved" partition as a mirror first, and then the C: partition (in your picture above, you have to right click and "remove mirror" from the extra disk first). I have no idea what it means to find an extent for a plex, nor tried to see if the mirror really and truly becomes a bootable disk. But at least it looks like it works.

screenshot showing mirrored system reserved and c: drives

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I think what this basically means (and thanks MS for being as cryptic as possible with this error), is that since you created the mirror from your primary partition first, that there is no space at the beginning of the drive for the system partition, which must be first. Probably the way to fix it would be to delete all partitions from the mirror drive and start over, creating the mirror of the reserved partition first, then the rest.

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How can I have Disk 1 be a complete mirror of Disk 0 so that if Disk 0 dies, Disk 1 is ready to run?

Searching did not help. so you could attempt stupid methods I would try.

clone it "Disk To Disk" sector by sector, with a cloning software like Acronis, then delete the part (like the partition) you know works properly and finish up in the OS.


I still think people are better off with simple MBR disks cloned outside the OS then Re-synced as neccessary, when the data is stable, instead of cloning bad to 2 disks :-) through continual mirroring.

That is just my opinion, and it requires way more manual effort. I have read about too many problems with dynamic disks , and even mirroring, to put myself through that.

My important stuff <------------------------> My backup, the 2 should not be too close to each other let alone continually mirrored :-) I am not running a server. If you are running a server, then down time is a problem, otherwise 90% of your data being perfect (the last sync) is better than kludging around and loosing 50% of it X2.

The OS ------------------> The OS backup Times 3 last weeks and last months and last years. Somewhere that I can get it back, but somewhere a virus and the OS itself is less likely to get to it. That would usually be an Image , a file, so I can pop it back on something.

The system backup would also be in a format that the OS I am trying to "fix" is not required to fix it. Again not running a server, so being able to get the OS booting again, is more important than having lost hardware for a day or even 2, or having lost the last few installs or e-mails.

I Always avoid (like a plague) allowing the system to mirror all our mistakes (the OS and I) to another drive, because when it will not even boot, duhh, neither would the exact mirror of it :-) For the OS itself I would far prefer to have a FEW older backups of it, than to believe that the hard drive itself is going to die. If your worried about the hard drive dying , then put a Backup of the OS on another drive, mirroring MS OSes is like shooting yourself in the foot twice :-) Once because you dont have an older backup you can fully retract, and the second time when your mirror will not boot too because it is the same.

you can get syncing software of all kinds to sync the data on the 2 drives so it is same. You can get cloning software for free that runs outside the OS.

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