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I just removed a disk to test our RAID 1 setup was working, and now I want to reintroduce that Disk, and have it continue living as a RAID1.

However, when I go into Disk Management the former RAID1 disk is marked "Missing" and the disk that WAS that disk is showing up separately.

How can I tell Windows that these disks contain the same data and that it should resume using them in tandem?

Thank you.

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up vote 3 down vote accepted

I doubt you can, just think about this: files have been changed when you pulled that one disk. logs, temporary files,... . You will need to resync I'm afraid.

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There's no way to do a sort of delta-resync? I mean, not much could have changed... – DTI-Matt Apr 30 '12 at 17:13
yeah. Working with software RAIDs on a Linux system, regardless of how little time the disk has been marked as "missing" or that the disks have 99.9% of the same content, it would have to rebuild it every time it was removed and added again. I don't think the software does an inventory of whats on the disk you just put in.. it just wipes it and starts the mirroring process – Safado Apr 30 '12 at 17:14
Goddamnit. Hahaha. Alright, thank you! And thanks for the quick responses! (I'll accept once the 6 minute timer has elapsed. :)) – DTI-Matt Apr 30 '12 at 17:15
At least you know it works and can now experience the pain of rebuilding :p – Lucas Kauffman Apr 30 '12 at 17:18
So we can remove and add harddisk whenever we want and the raid controller will "clone" the normal harddisk state when we insert new harddisk? – akhfa Feb 10 at 8:33

When you removed the disk from the array it was instantly dropped from the RAID. The disk is now in an unknown and out of date state. All new writes where to the single disk in the RAID. There is no journaling as such with RAIDs and this means it can't go back to when the disk was removed and only applies the changes since then.

There are benefits and disadvantages of RAID's. Make sure you have read up on them know if your configuration is appropriate for the type of data you are storing.

Also keep in mind that because of the lack of snapshoting/journaling you have no way to revert to a 'good state'. Plan for what would happen if you deleted all the files on the RAID or had a virus which was somewhat destructive.

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I would upvote you if I had the privilege :P Thank you too though! – DTI-Matt Apr 30 '12 at 18:08

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