backup fills up my disks

[donat]

The cron job is filling up my disk space with tmp.* directories. I normally have disk usage of 70%. Is that not enough? And what can I do to fix this. Every night the disk is full and I have to delete some tmp.* backups first. Then everything works fine afterwards. So I guess, that there is a endless loop somewhere, but I can't find out what is wrong.

I have debian 9 and latest vesta installed.

Any help is very appreciated.