Re: [Bobs-devel] incremental backup cleanup

[Rene R. <re...@gr...>]

On Sun, 2004-04-25 at 20:59, Joe Zacky wrote:
> Rene Rask wrote:
> 
> >
> >X should be the number of backup runs. 
> >Example: Backups run on monday,tuesday,and wednesday. 
> >I have chosen to keep 20 incremental backups. 20/3 is 6.6 times one week
> >(7 days) which gives 46.6 days to keep backups and we round the number
> >up to 47 to be safe.
> >
> >20/3 is the number of weeks
> >times 7 is the day count.
> >
> >I hope this makes sense.
> >  
> >
> It makes mathematical sense, but it's confusing and not intuitive. I 
> would never guess that by looking at the configuration screen. 
> Additionally, if someone changes the days of their backups, say from 3 
> to 5, that shortens the retention period even though backups have only 
> been running 3 times per week instead of 5. If we use this method, we 
> should calculate the retention date and show that on the screen so 
> people would know what it is.

A message like: "Backups will be retained for 45 days with the current
setting" should do the trick.
I would expect incremental to behave as I described. I guess my way of
thinking about the backup is a bit different from yours, so it is good
to explain this to people in an easy to understand way.

> >It seems like I'm wrong here. Guess we could use the find method. But
> >I'd still prefer the db method. That is better if we want to do more
> >advanced things in the future.
> >  
> >
> The database method is safer and more accurate because the modification 
> date in the incremental archive could be manually changed, say if 
> someone moved the directory or restored it from a tape backup. I'll play 
> with the database. The 'find' method was just so easy...

I suggest you take a look at the code where I use the db for searching.
You basically just make a search for files older than X. Just like you
can do with the current setup. It shouldn't be hard since its basically
done already :) 

Cheers