Shulou(Shulou.com)06/03 Report--

Problem description

The following error occurred when mapping block devices

[root@ceph-client /] # rbd map-image block/rbd0-name client.rbd

Rbd: sysfs write failed

In some cases useful info is found in syslog-try "dmesg | tail".

Cause of the problem

The reason for this error is that OS kernel does not support some features of block device mirroring, so the mapping fails to see which features are supported by the mirror.

[root@ceph-client] # rbd info block/rbd0-- name client.rbdrbd image 'rbd0': size 2 GiB in 512 objects order 22 (4 MiB objects) id: 15fe16b8b4567 block_name_prefix: rbd_data.15fe16b8b4567 format: 2 features: layering, exclusive-lock, object-map, fast-diff, deep-flatten op_features: flags: create_timestamp: Thu Dec 19 10:33:18 2019

You can see the feature feature column. Since my kernel only supports layering and nothing else, you need to disable some unsupported features. There are three ways

Three methods

1) dynamic disable

Rbd feature disable rbd0 exclusive-lock object-map deep-flatten fast-diff-name client.rbd

2) when creating a RBD image, only the layered feature is enabled.

Rbd create rbd2-size 10240-image-feature layering-name client.rbd

3) ceph configuration file is disabled by adding parameters such as parameters in global

Rbd_default_features = 1

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.