I set up a VM (using Bitnami running DokuWiki) and when I create manual snapshots, the size varies wildly between 1MB and 1GB. Nothing happens to the VM, the snapshots are created minutes apart from each other.
What is happening here? Am I missing something obvious? I want to set up auto backup, but if the manual creation of snapshots is not reliable I would not trust an auto system.
Cheers
The snapshots are created with incremental backups.
When incremental snapshots are performed, the current existing snapshot will be used as a baseline for subsequent snapshots. The system will create the new snapshot more quickly if it can use the previous snapshot and read only the new or changed data from the persistent disk.
Every new snapshot only contains new data or modified data. This is the reason why the sizes vary on each backup.
For more information in this regard, you may read this article from the GCP public documentation.
