@LEVI-HAVIV have you installed Nodejs? It appears the npm command (included when installing Nodejs) doesn't exist on your system.
Backing Up Mongodb Backed NodeBB
deltas might require less storage space over the long run?
If you are using deltas, you create increasing file system dependencies that make corruption more likely. To do so, you have to store lots of partial snapshots with the original(s) there for recreating. It can be done and most backup systems today do exactly this (Veeam, StorageCraft, Unitrends, etc.) It's the "assumed" method of storing snaps used for system backups. It makes the best of a bad situation.
However, if you are willing to use deltas, then you can do the same with dumps. This can be done in two main ways...
First, using MongoDump in a way I'm not familiar with but appears to work: https://dba.stackexchange.com/questions/107987/mongodb-incremental-backups
Second, by storing the resulting dumps on a compressed or deduped filesystem that will automate the delta functionality on disk. There are backup storage systems from StorageCraft that do exactly this for this purpose, for example. This method allows for delta-like storage efficiency, but with "full backup" style ease of restore so your restore admin need not know a complicated method for restore.
Dumps tend to be very small, so often a little compression goes a long way. But just in case they are huge, this handles it.
Heh.... Like the way I tee'd that one up fer' ye?
Good stuff. Better still that ye' scribed it here.
I talk backups all the time. I've been a senior advisor for multiple of the big backup players over the years and now my company builds its own backup systems for our own products. So we think about backups all the time.