Attempting to flush a cache tier pool fails with "Operation not supported".

This document (7022805) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Enterprise Storage 5

Situation

When attempting to flush a cache tier pool, for example if it is needed to remove the cache tier, where the backing pool is an Erasure Coded pool and this is used to store RBD (Rados Block Device) images, this fails with "rbd_header.160nov41ge8922x:head tid 1963229 (95) Operation not supported".

Resolution

It is needed to first migrate the RBD images header and metadata to another replicated pool.

Cause

Erasure Coded Pools only support storing RBD data, RBD image header and metadata information can only be stored on replicated Pools.

Additional Information

One possible option to migrate the RBDs may be to use for example rbd copy with the "--data-pool" option. Further more, for an Erasure Coded Pool to be used to store data it must have the "overwrite" flag set, which can only be done if all OSDs (Object Storage Daemons) are using Bluestore. For more information see the online SUSE Enterprise Storage 5 documentation.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.