File _log_XXXX in bucket

The size of bucket is growing very quickly.And i see many files that start with log.What are these files for? Can I delete them?

Rule of thumb: don’t delete anything manually unless Kopia is throwing errors. Let Kopia’s maintenance do its job and it will clean up what needs to be cleaned.

when i execute the following code, but it do nothing.

kopia maintenance --full --safety=none

kopia --help-long :

  maintenance set [<flags>]
                                   Set maximum number of log sessions to retain
                                   Set maximum age of log sessions to retain
                                   Set maximum total size of log sessions

There are default values. And kopia maintenance is fine on my other test machine.