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I was unlucky enough to have one drive in a four-drive volume set (no parity or error correcting) crash on me. I was in the middle of transferring about 15GB of data off the set onto another drive for backup when the drive stopped responding. All four drives were different makes and models of IDE hard disks that I had set up under Windows NT 4.0 Service Pack 3 (SP3). From what I understand about a volume set, it will continue to fill up the first disk until that drive is full and then proceed to the next disk until it is full and so on.
The drive that failed was the second in the chain. Sending the drive to data recovery specialists that recover the data directly off the platters was out of the question because of the cost involved. Even the data recovery specialists said they doubted there was anything I could do because of the file system. My situation would have been different if that data resided on one NTFS drive. Unfortunately, I was dealing with an NTFS volume set spanning multiple drives.
The drive that failed was under warranty, so I got a replacement. The new drive was blank of course, but everything about the drive was exactly the same as the failed drive. When I discovered the failure, I took all the other drives out and kept track of what order they were in and what controller they were connected to. I didn't back up the disk configuration from Disk Administrator, so restoring the volume set that way was not an option.
As if my situation wasn't bad enough, the original load of NT that I had used to create the volume set had passed to NT heaven. As a result, the configuration in the Registry was gone. Fortunately, the Microsoft Windows NT Server 4.0 Resource Kit, Supplement Two provides a valuable utility, FT Edit, that lets you manually configure a special set of disks in the NT Registry (e.g., volume set, striped set, striped with parity). When I created a new load of NT, I installed the drives in the same order as before. I went into Disk Administrator and let NT register the drives in the Registry. NT will see the drives as separate drives of unknown format. I then used FT Edit and manually made the drives show up as a volume set. If NT still only sees the drive as an unknown format, you can use the Disk Probe utility from the Resource Kit CD-ROM to check out the physical drives and the volume itself to make sure each has a proper ID (e.g., NTFS FT vs. just NTFS).
I rebooted NT, and the OS saw the new volume set and ran Scandisk (NT runs Scandisk whenever it sees a new NTFS drive in the system). At this point, things got interesting. The OS saw the middle drive as being blank, but the first drive contained the contents of what was on the volume set, so NT added all the files I had lost on the second drive, even with correct file size. All the files that the software restored were useless, but I did get all the files on the other three drives intact. If NT still only sees the drive as an unknown format, use the Disk Probe utility again. Most likely one of the drives in the set does not have a correct ID.
—Jon Balch
kaneda@lrdata.com
Register
I have used this technique twice to recover data-swap the cards and get your data back, then replace the old drive.
The drives (usually!) have to be exactly the same type/model for this to work, but the two times I have tried (both IDE unfortunately) I used the controller from the same manufacturer. The cards looked the same, and it worked fine. The second time the drives were the same size & from the same manufacturer, but the controllers differed slightly. I was able to recover the data, but the donor card also died about 4 weeks later.....
Jeremy Harrison August 15, 1999