I’m considering Restic and Backblaze B2 as my backup solution. I’m a little worried having read about the potential for unexpected restore costs. For example, I’ve read restoring lots of little files adds to the cost (reference). What are the things to look out for when backing up and restoring that can add to the cost? Are there any best practices to keep costs down?
Restic doesn’t write your files 1:1 to B2, but instead chunks their content into files according to a configurable pack size (16MiB by default). If you have a very large amount of data, you could look into increasing the pack size, although that comes with its own risks (see the docs above).
I doubt that this applies to files smaller than the pack size or a for example bitwise unique 17MB file would result in a (overly simplified) 16 MB and a 1 MB chunk or am i wrong here?
Most of these backup solutions try to reduce the amount of data backed up, so the system will process each file and determine if the contents changed and only upload new data. In this case if you modify the file you may end up with 2 16 MB chunks that have slightly different data, and only when the old backup expires and the pruning process completes would one of those chunks be deleted.
Smaller chunks sizes means you get more files written to S3, but less duplicate data when deduping without compression.
That is not what i have asked.