Win7 backups - doesn't remove deleted files from archive?

[scrawl]

I've been scratching my head over the way Windows 7 backup handles incremental archives.

To demonstrate:

1. Setup a Win7 backup to archive c:\test
2. Copy foo.txt to c:\test
3. Run Win7 backup
4. Browse the backup archive via the Restore Files GUI to confirm foo.txt was backed up.
5. Now delete foo.txt
6. Copy a new file, blah.txt, to c:\test
7. Run Win7 backup
8. Browse the backup archive and note that both foo.txt and blah.txt exist in the archive.

Seeing as how I deleted foo.txt, my expectation is it should not exist in the most recent archive. It would make a restore difficult, if I had to go through the entire drive and clear old data after a restore.

My understanding of a backup is it should represent a snapshot of the source at the time of backup.

Am I missing some fundamental logic here?

 

[SledgeDG]

Any incremental Backup I ever came across (including commercial Software for several K) never ever deleted files out of a created set. No offense, but I assume you're missing the logic behind it, yet it's so simple
How in the world should the Backup software know if the file you just deleted was an important one or not.
It would most definitely defeat the purpose by disabling you to restore such files at a later date.

The mechanic you describe is not found in backups but in applications that synchronize folder/drives/computers. There it's possible either depending on the direction of syncing that foo.txt would be deleted since it's no longer present at the source. And that exactly is, why sync software can't really replace backup software.

Same can also happen in certain Raid environments: if the controller gets damaged and starts to write garbage, the mirror drive does exactly what it's there for...mirrors the faulty file and you better have an offlinr backup handy
Granted, the chances that this constructed case happens are slim...there are methodes implemented to prevent those accidents.

-DG

 

[scrawl]

You're right, this is the first time I've looked at backup software in any great detail.

My impression was that an incremental backup would be more of a 'snapshot' of the hard drive at a given time and I would be able to view a 'timeline' of how the hard-drive contents changed by viewing the various revision dates. So if a file was deleted, it wouldn't appear in the latest increment but would appear in an earlier increment.

Thanks for the confirmation that it's working as intended.

 

[mborner]

It is my understanding that you deleted the foo.txt file from the backup archive, is that correct? You said nothing about deleting it from your C: drive. If I understand correctly, you never deleted foo.txt from C. So, when you created blah.txt, it was created right next to foo.txt on your C drive, none of which appear in your backup archive. Now, if you run backup again, of course it will backup both foo.txt and blah.txt. You deleted foo.txt from the backup archive, not the C drive. Had you deleted it from C, it would not have shown up in the next backup. Am I missing something?

 

[SledgeDG]

Sorry mborner but you seem to have misunderstood the problem. "foo.txt" was indeed deleted on the harddrive not in the backup set. (if you do that, depending on your backup software/backup media you could damage the archive's integrity)
so after incrementally backing up "blah.txt" they naturally both appear in the backup set. Everything else would simply defeat the purpose.

Had you deleted it from C, it would not have shown up in the next backup. Am I missing something?

It does not appear in the incremental part but is still part of the last full backup. The computer treats both sets as one (in order to restore your system to the most recent state) that's where the confusion stems from, I guess.
If that's still unclear just ask and I will dissect that matter for you

-DG

 

[mborner]

My apologies, SledgeDG, I somewhat misinterpreted your OP. In step 4 of your OP you said that you browsed to the backup archive to locate foo.txt and in step 5, you deleted it. I assumed you meant that you deleted it from the archive.

 

[SledgeDG]

No need to apologize, mborner. I'm not a native english speaker so the occasional misinterpretation is a given
Written conversation always lacks something compared to" face to face" anyways. That's why I said "ask if anything seems unclear"

-DG