# Are loop devices supported as OSD disks?

**URL:** <https://forum.ansible.com/t/are-loop-devices-supported-as-osd-disks/33974>\
**Category:** Ansible Project\
**Tags:** ubuntu\
**Created:** [October 6, 2020, 5:01pm UTC](https://forum.ansible.com/t/are-loop-devices-supported-as-osd-disks/33974 "2020-10-06T17:01:22Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Stephen\_Longofono](https://avatars.discourse-cdn.com/v4/letter/s/ed8c4c/32.png) [@Stephen\_Longofono](https://forum.ansible.com/u/Stephen_Longofono)\
**Post date:** [October 6, 2020, 5:01pm UTC](https://forum.ansible.com/t/are-loop-devices-supported-as-osd-disks/33974/1 "2020-10-06T17:01:22Z")

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I’m working on a minimal ceph deployment onto ubuntu 18.04 server VMs with loop devices. For my osds, the task “run ceph-volume lvm batch --report” is failing, apparently because the size key is never populated in ceph\_volume/util/device.py. As far as I can tell, loop devices are skipped over while enumerating device information in [get\_devices().](https://github.com/ceph/ceph/blob/befe3bc77af9e49ba04334ebccac0ba8b6eb8a18/src/ceph-volume/ceph_volume/util/disk.py#L738)

In my osds.yml, I have specified the device files for my loop devices, but otherwise I am using default settings. Is there a proper way to configure Ceph such that it will accept and use loop devices?

I realize that I could add additional disks to each VM, but for my use case it is preferable to have access to the backing files used by the loop devices.