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What's the best way to reset delta copy state?

Allen :

May 14, 2017

I deleted some files in the destination of the backups and want to reset the delta state to make sure all files are re-copied again.  One way I guess is to change the drive case (say from H to h) in the destation box of the profile ... after which I get prompted if I want to reset ... but there must be a better way?

Froggie :

May 14, 2017

I know if you change the "Detecting Changes" option to "Re-scan destination on every run," it will reset that snapshot on the next run.

I've changed it, did a MANUAL run of the backup job, then changed it back when I've done the same as you...

Alex Pankratov :

May 14, 2017


The delta state of files that have their backup copies deleted is automatically reset once the app sees these files gone. Ditto for backup copies that were _changed_ between the backup runs.

However, the caveat is not with resetting the delta state, it's with making the app notice that the files were deleted. This is what Froggies was getting at.

The default mode for a backup job is to scan backup location once, on the first run, then cache its state and NOT re-scan it on subsequent runs. This is the "Use destination snapshot" option of "Detecting changes" setting. The alternative is to re-scan destination on every run.

So if you kept your backup job at its default, then you need to make the app re-scan destination. One option is to do what you suggested (but this will also nuke delta state for all other files in the backup). Another is what Froggie said. The simplest option however is to run the backup manually using Ctrl-Go.

Holding Ctrl down tells the app to flush all cached data, including destination snapshot, thus forcing it to re-scan the backup location.

Allen :

May 15, 2017

Thanks Froggie ... and Thank YOU Alex!  :-)

LGS :

Jul 28, 2017

Is there a command line option to flush all cached data?

Alex Pankratov :

Jul 28, 2017



No, there is not.

That said, flushing all delta state data is as easy as deleting

    %LocalAppData%\Bvckup2\engine\backup-00xx\deltas

folder, whereby backup-00xx is a folder that you can get to by right-clicking on the job and selecting "Open folder > Configuration & Logging"

---

There are two other bits of data that is cached - the file system info and the destination file/folder index. Both can be reset by manually starting a job using Ctrl-Go (you can cancel the run immediately after it's started).

Alternatively, the latter can be reset by deleting snapshot.dat in job's backup-00xx folder and the former cannot be easily reset, not without editing the .ini file with job settings.

LGS :

Jul 28, 2017

Hmm.. i'm not clear on the purpose of the two other bits of data.

What I'm trying to test out is this:

I'm doing daily backups to a networked drive. This networked drive is rotated on a monthly basis, so what I'm trying to figure out is if bvckup can be made to do a full duplication each time the drive is rotated.

Does it still make sense for me to delete %LocalAppData%\Bvckup2\engine\backup-00xx\deltas at the start of each rotation?

Thank you.

Alex Pankratov :

Jul 28, 2017

Ah, OK.

"Delta copy" that I was talking about and that I assumed you were referring to is the per-file incremental copying algorithm used by Bvckup 2 as per https://bvckup2.com/support/forum/topic/739

For your setup things are far simpler. You just need to make sure that "Backup Settings > Detecting Changes" is set to "Re-scan". That's it.

The way bvckup2 works is that it scans source and destination directories and reconciles any changes so that destination looks as the source. It does this on every run. The "Detecting Changes" option merely controls if the program can assume that the contents of _backup_ remain the same between the runs or if they may change. In your case they may, so you need to tell the program to rescan your destination on every run.

LGS :

Jul 30, 2017

Hi Alex,

To make the the daily backups run faster, I have set it to "Use destination snapshot" as the networked drive is not rotated.

I read somewhere that switching to "Re-scan destination on every run" will slow things down.

So what I'm looking to do is to actually something that can trigger a "Re-scan" without permanently setting it to "Re-scan destination on every run".

Is there still some "snapshot" folder/file that I can delete to achieve this? Thank you. :)

LGS :

Jul 30, 2017

Hi Alex,

I just googled https://www.bvckup2.com/support/forum/topic/692

Will it trigger a "re-scan" if I delete all the "snapshot.dat" in %LocalAppData%\Bvckup2\engine\backup-00xx\ ?

Thank you!

Alex Pankratov :

Jul 31, 2017

Sorry about the delay replying.

Yes, correct. Deleting snapshot.dat will trigger a "re-scan".

I read somewhere that switching to "Re-scan destination on every run" will slow things down.


It really depends and it's something worth measuring. Basically, run your backup manually with Ctrl-Go and then look in "Preparing..." section of the log for:

2017.07.04 09:39:36         Scanning destination ...
2017.07.04 09:39:36             Completed in 344 ms

In this case snapshots probably don't make much sense as we are talking about shaving 300 ms off a backup run.

Generally speaking, you'd want to use snapshots:
(a) for real-time, frequently running backup jobs                           - or -
(b) for jobs going over the network with large amount of files    - or -
(c) for local jobs with very large number files (in millions)

LGS :

Aug 01, 2017

No worries for the delay, ok thanks. Deleting snapshot.dat is required in my case. Thank you.

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