Having a backup simplifies the process of transferring a service between machines, ensuring minimal inconvenience.
This is useful if your datacenter is on fire, if your server provider gets bought out by another corporation, or when shareholders decide that it is finally time to make more profit.
Restoring a snapshot involves stopping the service and reverting all files to their state at the snapshot's creation. This process can be accomplished in two distinct ways.
The safest one, the default one, is to download the snapshot in its entirety, verify that data is not damaged, and replace the service files with the files from the snapshot.
A somewhat riskier way is to overwrite the service files directly, without intermediate storage. It requires less space, but if the transfer goes wrong, you end up with a broken service.
To help reduce the impact, a snapshot is taken just before restoring.
Forgetting makes the snapshot inaccessible from the server, but deletion itself is reversible from cloud UI for some time (30 days for Backblaze by default).
Note that backups are independent per service. If you have services A and B backed up automatically every day in the morning, and then you back up service B manually at noon, then service A's next backup will be in the morning as usual, but B's backups will occur at noons.
* If you suspect that the list of snapshots is incorrect, try updating the snapshot list;
* If an inplace restore has failed, make sure that your cloud is accessible and your contract is active. Then try to restore either a snapshot that you tried to restore or a pre-restore snapshot that was automatically generated;
* If you do not have enough space on the disk for a safe restore, try restoring inplace.