How much faster does the cache make?

Getting Help
1

Hi,

how useful is the cache of restic? Does anyone have any general performance improvements (like xx% faster backups with cache enabled)?

Thanks in advanced

2

There is no accurate answer to your question as this depends greatly on the data, the backend and the network connection. But especially with remote backends restic’s cache will speed up most operations by a lot. I’ve just done some backups (using the --no-cache flag) on 2 different machines to demonstrate the difference.

Backup with 257 files (~4.3 GiB), rest-server as backend and ~3ms latency:
with cache: ~2 seconds
no cache: ~21 seconds

Backup with 199k files (~660 GiB), rest-server as backend and ~100-150ms latency:
with cache: ~20 seconds
no cache: ~1 hour

1 Like
3

Hi @764287
thanks for your stats. How big has your cache grown on both machines?

4

It’s ~2,4% of the raw-data on the first machine and ~0,03% on the second machine. But I’ve seen a cache as big as 15% of the raw-data aswell. :wink:

1 Like
5

Note that all metadata is saved in the cache. As a rule of thumb the larger your files are in average, the smaller is the metadata “overhead” and vice versa.