Re: OK to take hourly snapshots, then cull older ones?

[Duncan <1i5t5.duncan@cox.net>]

David Madden posted on Mon, 14 Oct 2013 21:05:33 -0700 as excerpted:

> I'd like to use BTRFS to do something like the old NetApp snapshot
> system:
> every hour or so, there'd be a snapshot, then the 23 of the snapshots
> during a day would be deleted, leaving just a day snapshot, then after a
> month, 6 of 7 snapshots would be deleted, leaving just a week snapshot,
> and so on.
> 
> Is this a reasonable thing to do in a cron job with a BTRFS filesystem?
> Apart from running out of space, are there any resources that might get
> used up?  Has anybody done this for a year or two in an active
> filesystem, and encountered success or weirdness?

There's discussion of this idea along with links to existing tools/
scripts for it, on the wiki:

https://btrfs.wiki.kernel.org

In particular, see documentation, guides and usage, use cases,
2. snapshots and subvolumes, 2.2. backups/time-machine.  However, that 
you didn't already know that was covered indicates that you either 
weren't aware of the wiki, or haven't read much on it recently, so 
there's likely a lot more information there that you'll find useful if 
you spend some time looking around and reading.

(I haven't done a whole lot with snapshotting myself as it doesn't fit my 
use case very well, but I knew about it from reading the wiki and had 
tagged it in my mind to look up again later should I need the 
information, so it was a matter of just a few seconds to find it again 
and type the path above so you could find it too.  Since I /haven't/ done 
much with snapshotting myself, I can't help much in saying which of the 
listed tools will be easiest, but that script link points at a list post 
with a pre-made script and crontab entries that look like they do just 
about exactly what you outline. =:^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman