Description of problem: In case RBD image doesn't have 'object-map' and 'fast-diff' features enabled, the dashboard will show its size as '0 bytes' if it's mapped to Linux client using RBD kernel module. However 'rbd info' command would still report the size correctly. For example, we have two images: 'img01' and 'img02'. Below is the output of 'rbd info' for these images: ~~~ rbd image 'img01': → size 4 TiB in 1048576 objects order 22 (4 MiB objects) snapshot_count: 0 id: 8a887425ae72cc block_name_prefix: rbd_data.8a887425ae72cc format: 2 → features: layering, exclusive-lock, object-map, fast-diff op_features: flags: ... rbd image 'img02': → size 2 TiB in 524288 objects order 22 (4 MiB objects) snapshot_count: 0 id: b08ad24b5cae6 block_name_prefix: rbd_data.b08ad24b5cae6 format: 2 → features: layering, exclusive-lock op_features: flags: ... ~~~ Note, that it 'fast-diff' is automatically enabled when enabling 'object-map' feature on the image, so i'm not quite sure which of two changes the behavior actually. RHCS dashboard shows 0 Bytes Provisioned or Total provisioned for 'img02' if it is mapped to a Linux client using the RBD kernel module. The size is however reported correctly if the image with the same feature set is created with gwcli and then exposed via iSCSI gateway. In our documentation [*] we do suggest only 'layering' and 'exclusive-lock' features to be enabled for the images which are mounted with RBD kernel module: ---✀--- 14. Configure the following: ① the desired image name, ② set Pool to the pool created earlier, ③ set the desired size of the image, ④ ensure Layering and Exclusive lock are the only enabled features: ---✀--- [*] https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/4/html/block_device_guide/the-rbd-kernel-module Is it an expected behavior for the dashboard, or are we hitting any bug with the size calculation, or maybe a documentation bug here?
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: Red Hat Ceph Storage 4.3 Security and Bug Fix update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2022:1716