On Tue, Mar 22, 2022 at 11:24 AM Robert Vasek <rvasek01@xxxxxxxxx> wrote: > > Hello, > > I have a question about cephfs subvolume paths. The path to a subvol seems > to be in the format of <subvol group>/<subvol>/<some UUID>, e.g.: > > /volumes/csi/csi-vol-59c3cb5a-a9ee-11ec-b412-0242ac110004/b2b5a0b3-e02b-4f93-a3f5-fdcef80ebbea > > I'm wondering about the <some UUID> segment. Where is it coming from, why > is there this indirection? It is the directory within the subvolume where the user's subvolume data is stored. When you fetch the mount path of the subvolume using `ceph fs subvolume getpath` command, you get the absolute path of the directory of the form, /volumes/<subvol gp name>/<subvol name>/<uuid>/ The indirection was introduced to allow storing subvolume's internal metadata within /volumes/<subvol gp name>/<subvol name>/, and to support features such as removing a subvolume while retaining its snapshots. For more details you can see, https://github.com/ceph/ceph/blob/v16.2.7/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v1.py#L33 https://github.com/ceph/ceph/blob/v16.2.7/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v2.py#L22 The UUID component of a subvolume's mount path is generated here, https://github.com/ceph/ceph/blob/v16.2.7/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v2.py#L168 > I suppose this means there can be multiple of > these UUIDs? No. There is only one such UUID directory that stores the user's subvolume data during the lifecycle of the subvolume. > Nowhere in "ceph fs subvolume{,group}" can I find anything to > list them (without actually traversing <subvol group>/<subvol>/*) however. > Or can you give me hints where to look for this in the code? `ceph fs subvolume ls` is used to list the subvolume names within a subvolume group, and `ceph fs subvolume getpath` or `ceph fs subvolume info` is used to fetch the mount path of a subvolume. There is no single command to list the mount paths of all the subvolumes within a subvolume group . Looking at https://github.com/ceph/ceph/blob/v16.2.7/src/pybind/mgr/volumes/fs/volume.py#L368 and https://github.com/ceph/ceph/blob/v16.2.7/src/pybind/mgr/volumes/fs/volume.py#L329 should provide clues on how it can be implemented. > > Thank you! > > Cheers, > Robert > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > Regards, Ramana _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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