Hi there,
On Wed, 17 Sep 2025, Matthew Pounsett wrote:
Re: Why is my v3 pool growing?
... the reported size of the v3 pool seems to rise and fall. Since
I don't think new v3 backups should be getting created?that would be
astonishing?I'm at a loss to explain it. And I'm really, really
curious what's up. I expect it to shrink over time as very-old
backups expire, and eventually just reach zero. I did not expect to
see it ever grow.
Does anyone have an idea of what's happening here?
Firstly, I'd be inclined to check the numbers in some way other than
by looking at the graph. :) It wouldn't be the first time that some
graph or other didn't perfectly reflect the underlying data. It may
be helpful to know exactly how much data we're talking about in the V3
pool (as the graphs aren't terribly precise) and also how many files.
It would be good to eliminate somehow any possibility that BackupPC
isn't the culprit, since BackupPC's graph just shows you approximately
how much data is in the pool directories, it doesn't actually know how
it got there.
Secondly, presumably you have
$Conf{PoolV3Enabled} = 1;
in your configuration file.
In that case when it's doing a backup, BackupPC will of course use the
V3 pool and matching data found there. Like you, I wouldn't expect
*new* V3 pool/cpool data to be written but I haven't done any tests at
all to see what might happen under oddball circumstances[*]. I see
setting $Conf{PoolV3Enabled} = 1; in the nature of stop-gap measure,
and I recommend setting it to 0 ASAP. Of course that supposes that
all your V3 backups are expired or considered to be of no more use.
If V3 backups still exist and you set $Conf{PoolV3Enabled} = 0; then I
guess that the worst that will happen is that files get copied to the
V4 pool instead of the existing V3 copies being used. That will take
some extra time and probably storage space, so we're back to asking
how much data (and perhaps how much free storage?), but that will only
happen once. Any remaining V3 backups would *not* then be cleaned up
by BackupPC itself, and would need to be deleted manually if required.
It wouldn't be a huge stretch of the imagination to think that the V3
pool might sometimes be used when it's not expected. I'd want to know
under what circumstances. To find out if this happens and if so when,
if it were my system I'd probably for example run cron jobs to dump
directory listings between backup runs, to view at my (ho-ho) leisure.
Maybe I'd also add some extra logging statements to the BackupPC code,
there are already a few which might give you some ideas, for example
in sub ScanAndCleanV3Pool() in BackupPC_nightly.
[*] For example hash collisions, system restarts, old tmpfiles?
--
73,
Ged.
_______________________________________________
BackupPC-users mailing list
[email protected]
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: https://github.com/backuppc/backuppc/wiki
Project: https://backuppc.github.io/backuppc/
