How big to make cache directory?

I recently started using restic for spooling some backups to cloud storage. Seems to be working great except my cache directory keeps filling up. I’ve created a 15G LVM volume just for the restic cache directory (daily backup is about 8G of data on disk) but this does not seem to be enough. The docs[1] specific to the cache don’t mention anything about cache size, only how to specify where it goes . Anyone know what the rule is for the size of the cache partition?

[1] Manual — restic 0.11.0 documentation

Cache size is going to scale approximately linearly with the number of objects stored in the repository. If you have a repository that contains a huge number of small files (such as Maildirs) then the cache is going to be large compared to a repository storing much more data, but representing fewer files (e.g. a large database or a media server).

Thanks for the explanation. Yeah, tons of small files (Linux servers). Around 8G per snapshot with nearly 1M files. I wasn’t sure if the “cache” was more of a temporary buffer, or something that needed to be maintained in concert with the snapshots. Seems like the latter. I’ll have to keep growing the LVM volume until I have enough history backed up.

PS: loving restic. Thanks whoever wrote it.

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There’s always the --no-cache option, but I think we all agree that you don’t want that (for performance reasons - the cache speed things up a lot).