78 Gigs of Free Space Show up on my C: Drive from nowhere - - Help

I

impactdax

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Jul 23, 2007
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So I had 2.5 gigs of space left on my c: drive, I then:

1. Connected an external Drive J:, then through windows vista backup and restore center tried to back up “files and folders”, but didn’t have enough room on my J: for more files. So, I

2. Erased an old “Windows complete PC Backup and Restore image of the entire computer” stored on the same external J: drive that I had made last October, since it was very outdated. It opened up a few hundred gigs on the J: drive and I proceeded with my file and folders back up to the J: drive.

3. Then some time later that day I looked at my C: drive. It had gone from 2.5 gigs of free space to about 80 gigs!

I don’t get it. I erased the image of my C: drive but it was erased off of my J: drive. I just opened the J: drive, found the folder with the image, right clicked and deleted. It was too big for the recycle bin, but I erased anyway. How would this event free up 78 gigs on my C: drive?

Questions:

1. Does the back-up and restore center store something on the c: drive in addition to the J: drive?

2. Is something in the Vista operating system smart enough to realize the J: drive mirror was gone and then deleted whatever files that may have been associated with it on the c: drive?

3. Could it have been old shadow copies, restore points or other things?

4. Could there have been an error for months and months in the calculation of my c: drive space?

5. Is there any way to determine what used to be on the space that is now unoccupied on the c: drive?

Thanks for any help
 
Not much info on how the machine is used, or what apps are in play, etc. If you have SQL installed, it is backup aware, and keeps log files of all changes that have taken place since the last backup so that the current state of the database can be restored.

When you next run a full backup, all of those log files are removed as they are uneccessary.

Other programs can behave this way as well, but it is more common with programs with database backends.
 
Sounds like filesystem issues. I usually recommend running chkdsk on any HDD showing issues.
 
Weird, for sure.

I don't think it'd HDD issues, you could run chkdsk anyway to be safe, but it doesn't sound like it.

My bet is more on temporary backup operation files. When did you check free space on C? Was it during the backup to J? If so, Windows could've filled C with temporary files that eventually got written to J.
Doesn't really explain 80GB of difference though.
 
My It guy called Microsoft and they seem to think that that vista uses shadow copies and ties them into restore points. They believe that a shadow copy/restore point was created when I originally made my mirror last october and that this shadow copy took up 15% of the total disk space (disk size is 750 gb, so it would have been over 100gb) or 30% of the remaining disc space after the mirror (I project about 250 gb's or so after mirror, which means about 75 gb). And that after I erased it off the J: drive and then performed another back-up (although it was a files and folder back-up, not a mirror back-up) that windows realized the mirror was gone and erased the shadow copy from my c: drive.

I can confirm that my system is only using about 8 gb for shadow copies now, and they only go back to the day I did the files and folder back-up, no sooner. So all of this sounds plausible. Here is the info from Microsoft:

Shadow Copy Space Management
There are storage spaces set aside for shadow copies both on the live volumes and on the backup disk for Complete PC Backup. You can check the used, allocated, and maximum shadow copy storage space values by running the following command from an elevated command prompt:
Copy Code
VSSAdmin list ShadowStorage
Used indicates how much space is currently taken up by shadow copies; allocated indicates the amount of space reserved for shadow copies (and so cannot be used for other purposes); maximum is the size limit that shadow copies are guaranteed to stay under.
Space allocation for shadow copies is automatic, meaning it cannot be set by the user. New space is allocated in fixed increments whenever the space previously allocated is used up. This is why the value shown for used space is always less than the value you see for allocated space.
For the live volume, the maximum shadow storage space allowed is determined when the first shadow copy is created—typically when System Restore is first enabled and a restore point is created during setup. The value is set to 30 percent of free space or 15 percent of the overall size of the volume—whichever is less. This maximum size is static. It will not change when more or less free space is available, nor will it change after the size of the volume has been adjusted.
However, you actually can manually adjust the size of this storage area by using the VSSAdmin tool from an elevated command prompt. For example, the command to increase the maximum storage size to 15GB on C:\ would be:
Copy Code
VSSAdmin Resize ShadowStorage /For=C: /On=C: /MaxSize=15GB
This tool originated on Windows Server®, where shadow copies for a particular volume could be maintained on another volume. In Windows Vista, shadow copies for a volume are kept on the same volume. Hence, the "for" and "on" volume has to be the same.
The backup destination disk for Complete PC Backup, on the other hand, has a fixed maximum shadow copy storage size of 30 percent of the disk space. This value is controlled by Complete PC Backup and cannot be changed manually. This shadow copy storage space is used for storing incrementals for Complete PC Backup.
Up to 64 shadow copies can be kept on a volume at any one time, provided there is enough space in the shadow copies storage area. Once the maximum space limit is reached, older shadow copies are deleted to make room for the new ones. Therefore, old restore points for System Restore are deleted when the shadow storage limit on the live volume is reached and old Complete PC Backups are deleted when the limit is reached on the backup disk. In addition, storing and editing other data on the backup disk may interfere with the normal process of aging old backups, causing old backups to be deleted at an accelerated rate​

Also, I am down to 72 gigs available just with normal use over the last week. Not storing anything new. I presume this is due to additional shadow copies requiring more storage.

Thoughts?
 
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