Subtask #5878
Updated by Loïc Dachary over 10 years ago
"work in progress":https://github.com/dachary/ceph/tree/wip-5878
The "abstract API":https://github.com/dachary/ceph/blob/wip-4929/doc/dev/osd_internals/erasure-code.rst#erasure-code-library-abstract-api is provided by dynamically loaded plugins.
* core change
** add *ceph osd pool create [name] [key=value] where *key* and *value* are arbitrary strings.
*** Update ceph osd pool create around "MonCommands.h":https://github.com/ceph/ceph/blob/master/src/mon/MonCommands.h#L494
*** Add a map<string,string> erasure_code parameter list to "pg_pool_t":https://github.com/ceph/ceph/blob/df17d021a6b517588d04cda7430ac11b2a83ef9a/src/osd/osd_types.h
* configuration example ( osd pool create keys interpreted by the plugin )
** ceph osd pool create poolname erasure-code-dir=/var/lib/ceph/erasure-code-plugins (mandatory)
erasure-code-plugin=jerasure (mandatory) erasure-code-m=10 (optional) erasure-code-k=3 (optional) erasure-code-algorithm=Reed-Solomon (optional)
** ... there can be more, depending on the plugin / algorithm
** we can probably generalize the mon command interface to have a key/value list type that will make this easy to plumb from the CLI (and trivial via ceph-rest-api).
* "src/osd/ErasureCodePluginInterface.h":https://github.com/dachary/ceph/blob/wip-4929/doc/dev/osd_internals/erasure-code.rst#erasure-code-library-abstract-api
* plugin loader and examples
** "draft implementation":https://github.com/ceph/ceph/commit/5a2b1d66ae17b78addc14fee68c73985412f3c8c
* unit tests
** in the test file ceph osd pool set-erasure-code <pool> plugin-dir src/test/osd/erasure-code-plugin
** simple minded xor based erasure code plugin that only supports M=2,K=1
** the plugin can be directed to trigger errors for tests purposes
** implement the test plugin to be the basis of a documented example to follow when implementing a new plugin