The support forum

Exclusive vs Shared backup directory

Alex Pankratov :

Sep 27, 2013

So I was thinking what the app should do if it is pointed at a non-empty destination directory.


As of now, it takes this as a personal offense and cleans the directory (by either deleting or archiving what's in there). It may also not delete anything, but this also affects its regular operations as it won't delete backups of any files deleted at source.

In other words, current operational assumption is that "destination directory is bvckup's and bvckup's alone". If someone else messes with it, the app will revert these changes.

While this is simple to understand, it appears to be not flexible enough and runs counter expectations of some users.


Here's a change I'm considering.

The backup can be set up to run in either exclusive or shared mode. In exclusive mode it will work as it does now. The shared mode is new and it is for adventurous souls - in this case the app will keep track of files it has so far put into the backup location and will ignore anything else it may find there.

This is an "adventurous" option because it comes with a plenty of opportunities to shoot oneself in the foot.


Also, this would tie well with the "Comparing" preference.

As you may remember, this preference controls whether the app should rescan destination directory on every run or it should cache destination contents, update it on every run and thus need to actually *scan* destination only on the first run. This translates into is a major performance boost in a lot of cases.

Under new exclusive/shared design, the shared mode implies maintaining the same kind of cache, so it's only natural to mesh these two preferences together. I never particularly liked "Comparing" preference as it's rather hard to explain in simple terms and I am concerned that it may be confusing.

So instead of "Comparing" option there'd be ... erm ... "Destination management" option structured as follows:

(  ) Exclusive - Bvckup has exclusive access to destination and it will maintain it an exact replica of the source

         [  ] Re-scan destination on every run

(  ) Shared - Bvckup will keep track of files that it puts in destination and will ignore all other files that might be already present there

         [  ] Re-scan destination on every run


Does this make sense? Or am I over-thinking this?

timmib :

Sep 27, 2013

Greetings Alex,

Since you asked ... <g> ...

I do think that you are 'over-thinking' this.  As it stands the destination can have backup copies of changed files as well as mirror image of original.  Now you're suggesting there's a need to throw other, unrelated files into a directory.  Doesn't make a lot of sense to me.  But, I'm perhaps missing something.  That is, I think you're anticipating the next layer of backing up files when they must be aggregated of burning to a disk, or whatever.  That would be an entirely different operation and I would not mix sources at the primary backup level.


Be well,  thanks for all the good work.


Alex Pankratov :

Sep 27, 2013

Hi Kim,

Thanks for your thoughts. To give this a bit of a context - this tracks back to the exchange we had with @highend, @jrothlis and @pgfitzgerald several weeks ago - In that thread @highend had a setup where all his separate backups were going into a single folder and he had a sensible explanation for it.

I, personally, put each backup into its own folder and I was assuming that it was a natural thing for everyone to do. Apparently it's not and to each his own. There are some scenarios when people prefer to point all backups to a single folder, or to manually add random files to the backup, or to start with an existing backup directory that is not, however, a precise replica of the source. Various things that seem odd to *me*, but which are actually reasonable in retrospect. So I am trying to accommodate these if possible.


jrothlis :

Sep 28, 2013

Remember the *other* discussion about less options? =)

Alex Pankratov :

Sep 28, 2013

I do :)

I really don't like the "Comparing/Scanning" option. Not in its current form, I think it's confusing and it doesn't really belong to the basic backup config. And since I want to nuke it, I thought that, perhaps, I can rather change it into something else. Hence this thread.

scribbly :

Sep 29, 2013

That's funny... not long ago I set up some 'backups' to aggregate different directories from my HD into a single directory on my USB drive, obviously with issues. But I didn't worry as it's not essentially a backup option, just something that I wanted to do.

So, not a big thing for me, but certainly something I'd use.

WiseOldElf :

Sep 30, 2013

i've been caught out by bvckup2 trying to delete everything else in a folder, and don't imagine i'll be the only one to fall foul of that 'feature' :)

Alex Pankratov :

Sep 30, 2013

@WiseOldElf - What were you expecting to happen?
Sorry if we might've already discussed that, I just can't remember if we did.

Alex Pankratov :

Sep 30, 2013

Alright, a stop-gap measure for now -

Once I push the public beta out of the door, I'll revisit this. What I'd like to do is to make the 1st run special - to make it scan destination and decided if it may happen to contain a close copy of the source. If so, then it will assume that Bvckup is being used to take over an existing backup and it will just quietly proceed. Otherwise, it will spit out a warning like the one above.

And then even later on I will try and get this exclusive/shared support in, but I still want to see if it's really needed.

Deipotent :

Sep 30, 2013

I encountered this issue with Bvckup deleting existing contents of dest folder (luckily I had a backup), and thought I had made a comment about displaying a warning alert.

For me, the new alert is fine, although I would have the text " will delete or archive all folders and files that do not exist in the source." in bold to draw attention to it.

Alternatively, move that line up, so the first line after WARNING reads:

"Selected backup location exists and it's not empty. Any folders or files that do not exist in the source may be deleted will be deleted!"

I think I prefer the latter option.

Alex Pankratov :

Sep 30, 2013

There *was* an alert, but it was just meekly stating that the folder existed and asked if to proceed.

I just pushed the update out, so I'll attend to bolding and exclamation marks in the next release.

WiseOldElf :

Oct 01, 2013

well, in  a curious way, i think that what's currently happening is 'correct', it's just that it wasn't something that i thought about at the time :)  my caution to you is, as i mentioned, that i suspect i won't be the only person to look at it the same way...

by way of background: having been caught out with windows vagaries over the years, i use one 'data' folder, and sub-folders within it for each application.  some of these sub-folders are more dynamic than others, so i had them on a shorter backup cycle and then it dawned on me that each backup was actually 'deleting' the other sub-folders each time it ran.

my hunch is that, whilst perhaps not correct from a purist sense, operating in a more 'defensive' way is going to cause less angst :)  people who lose their data, even when it's their own fault, tend to like to have a target for their wrath !

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