Hi @Fabrice, I also experimented with pack sizes a while ago: Repack smallest packs
Back then, I had different pack sizes and some as small as 4 MB. I did not systematically evaluate the runtime with different pack sizes. My concern was mainly the number of files (and inodes on disk) and the runtime of `restic check` and `restic prune` commands. In my experience, a packsize between 16 MB and 64 MB is reasonable. I now settled with 64 MB, but if I would start from scratch, I probably would not bother to change the default of 16 MB.
If my understanding of the prune command is correct, the optimal pack size depends on how big your files are and how frequently they change. If most files are large videos which you record once and then store forever, you can use large pack sizes (and few packs). If some fraction of files are only a few kB in size and change every day, then prune would have to rewrite those large packs during prune and smaller pack sizes make it easier to delete or rewrite only the affected data.