Hello, my goal is to back up a proxmox cluster with rbd-mirror for desaster recovery. Promoting/Demoting, etc.. works great. But how can i access a single file on the mirrored cluster? I tried: root@ceph01:~# rbd-nbd --read-only map cluster5-rbd/vm-114-disk-1 --cluster backup /dev/nbd1 But i get: root@ceph01:~# fdisk -l /dev/nbd1 fdisk: cannot open /dev/nbd1: Input/output error dmesg shows stuff like: [Thu Mar 19 09:29:55 2020] nbd1: unable to read partition table [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) Here is my state: root@ceph01:~# rbd --cluster backup mirror pool status cluster5-rbd --verbose health: OK images: 3 total 3 replaying vm-106-disk-0: global_id: 0bc18ee1-1749-4787-a45d-01c7e946ff06 state: up+replaying description: replaying, master_position=[object_number=3, tag_tid=2, entry_tid=3], mirror_position=[object_number=3, tag_tid=2, entry_tid=3], entries_behind_master=0 last_update: 2020-03-19 09:29:17 vm-114-disk-1: global_id: 2219ffa9-a4e0-4f89-b352-ff30b1ffe9b9 state: up+replaying description: replaying, master_position=[object_number=390, tag_tid=6, entry_tid=334290], mirror_position=[object_number=382, tag_tid=6, entry_tid=328526], entries_behind_master=5764 last_update: 2020-03-19 09:29:17 vm-115-disk-0: global_id: 2b0af493-14c1-4b10-b557-84928dc37dd1 state: up+replaying description: replaying, master_position=[object_number=72, tag_tid=1, entry_tid=67796], mirror_position=[object_number=72, tag_tid=1, entry_tid=67796], entries_behind_master=0 last_update: 2020-03-19 09:29:17 More dmesg stuff: [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:29:55 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: 95 callbacks suppressed [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 0 [Thu Mar 19 09:30:02 2020] buffer_io_error: 94 callbacks suppressed [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 0, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 1 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 1, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 2 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 2, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 3 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 3, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 4 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 4, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 5 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 5, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 6 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 6, async page read [Thu Mar 19 09:30:02 2020] block nbd1: Other side returned error (30) [Thu Mar 19 09:30:02 2020] blk_update_request: I/O error, dev nbd1, sector 7 [Thu Mar 19 09:30:02 2020] Buffer I/O error on dev nbd1, logical block 7, async page read Do i have to stop the replaying or how can i mount the image on the backup cluster? Thanks, Michael