Hey Sascha, I ran into this issue too and was quite puzzled. There is this open PR which suggests that group snapshot exports are unsupported as of now: https://github.com/ceph/ceph/pull/40808 The best thing I could figure out to get consistent snapshots with multiple rbd's is to fsfreeze my filesystems (using libvirt, so domfs{freeze,thaw} in my case) and make individual snapshots of the rbd images. Kind regards Matthias On 3/5/26 15:46, Sascha Lucas via ceph-users wrote:

Hi,

I created a rbd group to snap multiple images consistent regarding point in time:

# rbd group image ls vm1010 rbd/5c6acb6f-a6ea-49f4-b709-ca10d423ad42.rbd.disk1 rbd/770e7d64-128a-4e85-9906-b49332b0df26.rbd.disk0

# rbd group snap ls vm1010 ID              NAME    STATE 4c8d35cc0d0177  snap-1  complete

But how do I export/export diff a group snap? The individual images show no snaps:

# rbd group snap info vm1010@snap-1 rbd group snapshot 'snap-1':     id: 4c8d35cc0d0177     state: complete     image snap: .group.1_18efdc6b8b4567_4c8d35cc0d0177     images:         rbd/5c6acb6f-a6ea-49f4-b709-ca10d423ad42.rbd.disk1 (snap id: 202)         rbd/770e7d64-128a-4e85-9906-b49332b0df26.rbd.disk0 (snap id: 203)

# rbd info rbd/5c6acb6f-a6ea-49f4-b709-ca10d423ad42.rbd.disk1 rbd image '5c6acb6f-a6ea-49f4-b709-ca10d423ad42.rbd.disk1':     size 22 GiB in 5632 objects     order 22 (4 MiB objects)     snapshot_count: 1     id: 18efd69508379e     block_name_prefix: rbd_data.18efd69508379e     format: 2     features: layering, exclusive-lock, object-map, fast-diff, deep- flatten, operations     op_features: group     flags:     group: rbd/vm1010     create_timestamp: Tue Nov 15 12:59:56 2022     access_timestamp: Thu Mar  5 13:59:29 2026     modify_timestamp: Thu Mar  5 14:00:06 2026

# rbd snap ls rbd/5c6acb6f-a6ea-49f4-b709-ca10d423ad42.rbd.disk1 <no output>

Ceph version is v20.2.0 with cephadm.

TIA, Sascha. _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io

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