Hi, what is the purpose and effect of these configuration options? bdev_async_discard bdev_async_discard_threads bdev_enable_discard They are not mentioned on docs.ceph.com. They read as they would enable a regular trim job on OSDs where the hardware supports trimming/discarding. How often would this operation run? On a virtual test cluster where the OSDs are backed with qcow2 files and are presented to the VM as SSDs with discard they seem to have no effect on the size of the qcow2 file. With a normal filesystem an fstrim operation will reduce the size of the qcow2 file. Regards -- Robert Sander Linux Consultant Heinlein Consulting GmbH Schwedter Str. 8/9b, 10119 Berlin https://www.heinlein-support.de Tel: +49 30 405051 - 0 Fax: +49 30 405051 - 19 Amtsgericht Berlin-Charlottenburg - HRB 220009 B Geschäftsführer: Peer Heinlein - Sitz: Berlin