diff --git a/doc/ceph-volume/lvm/prepare.rst b/doc/ceph-volume/lvm/prepare.rst index 9c684c00138..2fa1e262405 100644 --- a/doc/ceph-volume/lvm/prepare.rst +++ b/doc/ceph-volume/lvm/prepare.rst @@ -235,6 +235,33 @@ work for both bluestore and filestore OSDs:: ceph-volume lvm prepare --bluestore --data vg/lv --crush-device-class foo +.. _ceph-volume-lvm-multipath: + +``multipath`` support +--------------------- +Devices that come from ``multipath`` are not supported as-is. The tool will +refuse to consume a raw multipath device and will report a message like:: + + --> RuntimeError: Cannot use device (/dev/mapper/). A vg/lv path or an existing device is needed + +The reason for not supporting multipath is that depending on the type of the +multipath setup, if using an active/passive array as the underlying physical +devices, filters are required in ``lvm.conf`` to exclude the disks that are part of +those underlying devices. + +It is unfeasible for ceph-volume to understand what type of configuration is +needed for LVM to be able to work in various different multipath scenarios. The +functionality to create the LV for you is merely a (naive) convenience, +anything that involves different settings or configuration must be provided by +a config management system which can then provide VGs and LVs for ceph-volume +to consume. + +This situation will only arise when trying to use the ceph-volume functionality +that creates a volume group and logical volume from a device. If a multipath +device is already a logical volume it *should* work, given that the LVM +configuration is done correctly to avoid issues. + + Storing metadata ---------------- The following tags will get applied as part of the preparation process