I would like to preseve snapshots whether or not a storage is available or not. Think about working on a laptop where a remote storage may not be available.
If a storage is offline, duplicacy backup does not run. Is it possible to “cache” a snapshot in this case locally, and upload to the storage if back online?
Maybe this is already included, but I did not see it in duplicacy CLI or Web-GUI.
I don’t think this is possible, caching a storage i mean.
What you could do, but it’s a total headache is have a local storage (on your own laptop) to which you backup, then copy to remote, then prune local again (so that you always have 2 backups left on local – so that deduplication works).
You could do that but i think the overhead is way too much for the minuscule benefits, since most of the time of the backup process is spent while uploading the chunks to the remote, and not while backing up per se (reading the files from your disk), so even if you backup locally, you will still waste the same amount of time while doing the copy from local to remote.
This should be a feature request. Time Machine does it and it is an awesome feature!. Just because you are in the desert working on your next best thing does not mean that you should forgo periodic backups and versioning.
Would that be easy to implement consistently? Probably not, but it’s worth to file a feature request anyway 
I found it a horrible and buggy feature. On one laptop i’m having this problem that time machine always fille up the ssd, even though i have disabled all backups. 300GB+ of “system” usage… really uncool. 
Plus, you just waste storage space with this. There is no actual backup since all the data still resides on the device that you’re trying to protect.
Unless you have a corrupted filesystem that is “prunable” storage – when more space is needed the system will automatically free that. You can try to nuke that, run First Aid from recovery partition and then see if the issue re-appears.
Right, it wont’ help against hw failure but this still provides protection against user error and maintains the cadence of your backups so you can always rely on having consistently timed history at any time.
I’d argue that not taking advantage of free space for anything, even for minor benefit, is wasting it – you paid for that SSD – it’s a shame to keep it empty
Exactly, snapshots are not exclusively about hardware failure, but also to preserve revisions. As it is, but “features” are not available if a remote storage is not accessible, but revisions could be available if snapshots are stored locally.