Cache size recommandation

Well… it may depend on your change ratio and structure of your data. Let me check that on my two other repos…

This is a 2.8 TB repo, which holds the backups of a mail cluster:

[root@kopia ~]#  kopia blob stats --prefix=q
Count: 3773
Total: 71.9 GB
Average: 19.1 MB
Histogram:

        0 between 0 B and 10 B (total 0 B)
        0 between 10 B and 100 B (total 0 B)
        0 between 100 B and 1 KB (total 0 B)
      101 between 1 KB and 10 KB (total 476.3 KB)
       15 between 10 KB and 100 KB (total 484 KB)
       23 between 100 KB and 1 MB (total 12 MB)
      182 between 1 MB and 10 MB (total 0.9 GB)
     3452 between 10 MB and 100 MB (total 71 GB)

So… 71 GB for 2,8 TB

And this one here…

[root@kopia kopia]#  kopia blob stats --prefix=q
Got 10000 blobs...
Got 20000 blobs...
Got 30000 blobs...
Got 40000 blobs...
Got 50000 blobs...
Count: 57871
Total: 145.9 GB
Average: 2.5 MB
Histogram:

        0 between 0 B and 10 B (total 0 B)
        0 between 10 B and 100 B (total 0 B)
        0 between 100 B and 1 KB (total 0 B)
    44496 between 1 KB and 10 KB (total 192.5 MB)
     3531 between 10 KB and 100 KB (total 128.3 MB)
     1205 between 100 KB and 1 MB (total 329.8 MB)
      132 between 1 MB and 10 MB (total 258 MB)
     8507 between 10 MB and 100 MB (total 145 GB)

This is a 56 TB repo of file server, that has been kopia-snapshotted for at least a year now. As you can see, its “only” 145 GB for 56 TB. So, maybe the chunksize/blobsize needs to be adjusted to the type of data/filesizes, which are mostly brought into the repo.