I got a real stumper for you. If you're interested.
I got a new drive as a backup and did a full backup with freefilesync (identical to the main drive).
1) The free space on the backup drive is showing 6GB more than the main drive.
The backup drive has 16.4GB free and the main drive has 10.4GB free. (I did not say that backward. The BACKUP drive that shows 6GB MORE free space.)
2) I took out the exclusions in freefilesync and that was only 20kb in a system volume information folder (which it errors to sync anyway, and yes the Recycle Bin is empty).
3) I selected all the files in Explorer and hit properties and they were about 20k bits MORE on the MAIN DRIVE (which are the excluded files from 2).
4) This is what the properties show with all folders/files selected, which show the same amount of files and folder. But under My Computer, the backup drive still shows 6GB MORE free space.
Main Drive: Size: 7.26 TB (7,983,381,080,639 bytes), Size on Disk: 7.26 TB (7,983,405,719,552 bytes)
Backup Drive: Size: 7.26 TB (7,983,381,080,639 bytes), Size on Disk: 7.26 TB (7,983,405,699,072 bytes)
5) I thought this might be a allocation unit size issue, so I created a text file with a few lines of text and they both 4096 bytes.
6) Disk Management shows both drives with identical sizes and each with one big identical sized partition.
7) I connected the original backup drive and it shows 10.4GB free, exactly the same as the main drive.
8) I created a FFS from the original backup drive to the new backup drive and it said everything was synced...but still the new backup shows 6GB MORE free than the original backup and the main drive.
9) I copied a 14GB file to the new backup drive just to see if it would actually fit and it did!
Thoughts?
Free Space Mismatch on backup drive FreeFileSync
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Theory: Maybe the original hard disk has accumulated 6GB of bad sectors. This would explain all the symptoms. Also I would check for which of the two drives the following equation still holds:
total disk space = size on disk + free space
total disk space = size on disk + free space
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The main drive and original backup both show the 6GB free. Only the new backup is showing 16GB free. If it was bad sectors, BOTH the main drive and original backup would have to have the same bad sectors.
I also ran a tool to look at filename length just to make certain I didn't have any files in long nested folders that didn't copy and it didn't find anything. (I didn't think it would since manually selecting all files shows them being the same size as the main drive)
I'm really stumped as to what to do. I think I might retry copying everything but just doing a smaller chunk at a time. The first time I filled the new backup was a single FFS run for the entire 7+ TB of content. It took a couple days which is why I'm hesitant to do it again but I'm really stumped.
I really think I went through all the steps that could possibly identify the issue, didn't I?
I also ran a tool to look at filename length just to make certain I didn't have any files in long nested folders that didn't copy and it didn't find anything. (I didn't think it would since manually selecting all files shows them being the same size as the main drive)
I'm really stumped as to what to do. I think I might retry copying everything but just doing a smaller chunk at a time. The first time I filled the new backup was a single FFS run for the entire 7+ TB of content. It took a couple days which is why I'm hesitant to do it again but I'm really stumped.
I really think I went through all the steps that could possibly identify the issue, didn't I?
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The ultimate test is to run a binary-comparison of both backup drives using FreeFileSync. If both sides come up as identical, this would still not explain the differences in free space, but at least you can be certain that all the data is physically available and uncorrupted.
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How do I do that? I always start by clicking the compare button. As of now, it says they are identical. It's currently on "File time and size". Is there a "binary-comparison" option somewhere?
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Yes, compare by "file content". FreeFileSync has this option precisely for data verification and consistency checks.
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Okay, yeah I thought that might have been it so I ran it yesterday. It must have finished just fine because this morning I'm looking at a blank FFS page (7.26 TB of content, so we're talking 18ish hours). I should also note, I have "VerifyCopiedFiles" set to true and have had that enabled since I first installed FFS so the original backup and this new backup were both verified when copied originally.
I'm still showing 16GB free on the new backup, the main drive and original backup still show only 10GB free.
I just don't understand where these 6GB have gone and I'm not willing to let it go as it's obviously somewhere. The capacity of all 3 drives show exactly as 8,001,560,768,512 bytes.
I'm still showing 16GB free on the new backup, the main drive and original backup still show only 10GB free.
I just don't understand where these 6GB have gone and I'm not willing to let it go as it's obviously somewhere. The capacity of all 3 drives show exactly as 8,001,560,768,512 bytes.
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Maybe the "Main Drive" and the "Original Backup" both have some OEM Software on them, on a hidden partition perhaps? I know that seems simple but...
Why don't you compare the number of Folders in each via cmd. I had an instance recently where some Folders were not Copied for some reason.
Why don't you compare the number of Folders in each via cmd. I had an instance recently where some Folders were not Copied for some reason.
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I just reran the "File Content" Compare in FFS, this time from the Original Backup to the New Backup (thinking there might be unreadable hidden or system file somewhere on the main drive blocking me) and it only is showing the 20kb file in a system volume information folder).
I'm at a total loss here. I just do not understand how both all 3 drives can show the exact same amount of total space, exact same amount of partition space, exact same amount of used space, yet one drive has 6GB more free space than the other two...I mean, what?!
Keep in mind point 4 in the OP. When I select all the folders on the main drive or original backup it shows the same amount of size as the same selected folders on the new backup but when I look at the drive properties there is the 6GB discrepancy on the new backup drive only. Obviously this lead me to believe it was a hidden or system file somewhere but even when removing all exclusions, FFS is not finding it, when I unhide hidden/system folders, I'm not seeing it either.
Unbelievably perplexed!
I'm at a total loss here. I just do not understand how both all 3 drives can show the exact same amount of total space, exact same amount of partition space, exact same amount of used space, yet one drive has 6GB more free space than the other two...I mean, what?!
Keep in mind point 4 in the OP. When I select all the folders on the main drive or original backup it shows the same amount of size as the same selected folders on the new backup but when I look at the drive properties there is the 6GB discrepancy on the new backup drive only. Obviously this lead me to believe it was a hidden or system file somewhere but even when removing all exclusions, FFS is not finding it, when I unhide hidden/system folders, I'm not seeing it either.
Unbelievably perplexed!
