[Duplicity-talk] Only sync remote metadata from primary backup chain

[Markus Doits]

Hello,

I've been using duplicity to backup since 2014 with a full backup every 3 
months, so I have some secondary backup chains. Additionally backups go to 
multiple separate places (each having multiple backup chains). My local cache 
folder is now over 70gb big and I had the idea to delete the cache for the 
secondary chains to free up space - since they are only needed when restoring 
files, but not for new backups (to the primary chains).

So I deleted the cache files (for example 
duplicity-full-signatures.20141106T121637Z.sigtar.gpg) and reclaimed a lot of 
space.

But after the next backup run, I saw this in the logs:

Synchronizing remote metadata to local cache...
Copying duplicity-full-signatures.20141106T121637Z.sigtar.gpg to local cache.
Copying duplicity-full-signatures.20150505T234205Z.sigtar.gpg to local cache.
Copying duplicity-full-signatures.20150904T234123Z.sigtar.gpg to local cache.
Copying duplicity-full-signatures.20151205T004128Z.sigtar.gpg to local cache.
...

Is this normal? If yes, is there an option to skip synchronizing the secondary 
backup chain's metadata I don't find in the man page? If I understand it 
correctly, I only need them to restore files from those chains, since I will 
not do new incremental backups to that secondary backup chains. I'd imagine 
duplicity to only sync the metadata in the case I want to restore files from 
those chains.

Or is there any other way to reduce the cache usage (besides completely 
deleting the remote backups which I don't want).

For reference: I'm using duplicity with duply (http://duply.net/), so maybe 
this triggers the behavior I describe if this is not normal behavior.

-- Markus