A few days ago I ran into a peculiar and rather perturbing glitch on my Dell XPS 8700 system running Windows 8.1.
My internal storage configuration is set up as follows:
- Primary Drive C:\ SSD
- Storage Space (I) D:\ and Storage Space(II) E:\ These are a pair of drives that share a 16 TB (virtual) storage pool with two-way mirroring running on 2 x 2TB HDDs. I have split the storage space into two so that I can distinguish between dynamic files (those that require regular backup) and static files (those that are required on the system but could be reloaded from outside resources if necessary) and handle them appropriately.
In addition to the above, I have a pair of external HDDs (L:\ & M:\) connected via USB ports and an integrated DVD - RW drive (H:\). This configuration has run successfully for several months now.
A day or so before the incident that I describe below I attached a further device via a USB port (a REV 70 drive that the OS handles as a CD drive). This drive was being used to load a set of files transferred from my previous system. I cannot swear to the drive letter that was assigned to the device - I just checked that the expected folder was available, and that the transfer of the required files ran as expected. However the REV drive is currently back on line, and has been given the drive letter F:\, so I believe that must have been the letter originally assigned. At that point I left the REV drive and relevant disk online/loaded with the intention of doing a folder-by-folder check of the transfer.
Hoping that the the preceding information is sufficient without including the irrelevant, I now come to the incident that is causing me concern:
At some time the drive letters associated with the internal HDDs were changed, Storage Space (I) becoming drive E:\, and Storage Space (II) becoming drive F:\. At the same time the REV drive (which I presume had been drive F:\) was assigned the letter D:\.
I believe that I can pin the time down to a twenty-four hour period between two scheduled backups. Part of my daily backup routine is to do an incremental backup of drive D:\ using StorageCraft's ShadowProtect. The log for 12:01 AM on September 3 shows the source of the backup data to be Storage Space (I) (D:\) NTFS, and that for the backup twenty-four hours later is shown as Storage Space (I) (E:\). Strangely enough the change of assigned letter didn't seem to faze ShadowProtect (it simply added an incremental image file to the chain previously used for drive D:\ which seems to have successfully incorporated the data from what was at that point drive E:\). I assume that ShadowProtect must keep track of the source at a more fundamental level than the data path.
I believe that something of the same sort must be true of the browser and mail systems that I use, because it took another 15 hours or so before the fact that an application was failing because it could not find an expected file drew attention to the problem with the file paths. At that time, I removed the REV drive (showing as D;\) and used the Disk Management facility to change the drive letters of Storage Space (i) and Storage Space (II) back to their original settings. This appeared to fix any immediate problems, although I did note that drive E:\ was now Disk 4 on the Disk Management list, and drive D:\ was Disk 5 (the reverse of the original setup).
I thought at first the drive letter re-assignment might have occurred at the same time that I did a restart in safe mode to replace a driver (as requested by by a software supplier trying to sort out another bug). I have since abandoned this idea, as it turned out the timing was wrong, but before I had come to this conclusion I had duplicated the safe mode restart to see if I could recreate the problem. This did not affect the file path drive letters, but I notice that Disks 4 and 5 have gone back to being drives D:\ and E:\ respectively.
At the moment everything seems to running smoothly again, but I am concerned that the problem might show up again unexpectedly, possibly causing more havoc than it did this time. Can anyone point out anything I may have missed, or any possible errors in my disk management set-up? . Has anyone any suggestions as to how I can pin down just what went wrong and when?