Saturday, October 1, 2011

No Good Deed Goes Unpunished

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Earlier today I was helping someone troubleshoot a problem with their computer.   In order to pinpoint a display issue, I installed their video card into one of my computers to verify it was the problem.  Since the box I have configured as my file server is the only one of my computers with a PCI-E slot, I installed the video card in question into that box.  The card was indeed bad and I thought nothing of it again until I noticed that one of the shared hosted on that box was no longer  accessible over the network.

On this box I have two 1.5TB hard drives, each divided into a 500MB and a 1000MB partition.  The two 500MB partitions are mirrored and host what I consider to be critical data, such as the digital family photo album (you know, the things that the wife would literally kill me if they disappeared).  The two 1000MB partitions are a spanned volume, and host data considered to be non critical, or in other words things I can pull out the CD's and/or hit the web and re-download it.  The critical data partition is the one I could still access, and the server said it was a degraded mirror.  Computer management said one of the drives was unavailable.  And for what it's worth, the computer is running Server 2008R2.

What had happened was that when I put my video card back into the computer, the power cable for the missing hard drive got caught by the corner of the video card, and it was pulled out of the drive.  Easy fix right?  Not this time.  I reconnected power to the drive and verified that it was found by the BIOS before proceeding.  However, when I booted into Windows, the drive showed up as a foreign volume, and the two partitions were not recognized.  I right clicked on the partitions and selected reactivate volume, but no dice.  Windows responded with "The Plext is missing"

So I right click on the unrecognized volume and my only option is to import foreign volume.  This strikes me as a very scarey option, since its probably going to make changes to the disc, but it's my only choice at the moment.  Punching "import foreign volume" and "the plext is missing" into Google, I find a couple posts on various forums with the exact same problem and stating that importing the foreign volume indeed fixed the problem.  So I hold my breath and proceeded, and Windows then immediately brought the spanned volume back online (the non critical data), and two identical volumes of the critical data, rather than one mirrored volume.  So I deleted one of the identical volumes and re-mirrored it.  The mirror is re-synchronizing as I type this, and everything is now accessible again.

Moral of the story, RAID is not a backup.  RAID 1 is not a backup.  But in this instance, it saved me from having to either pull out a couple dozen DVD-R's or copy everything back across the network tonight.   Not bad at all since I had 6 sugared up kids running wild through the house during all of this.  All I really wanted was to stream a video from the server to the Playstation 3.


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