Flushing

You can flush the cache file with the rbd command, specifying persistent-cache flush, the pool name, and the image name before discarding the persistent write log (PWL) cache. The flush command can explicitly write cache files back to the OSDs. If there is a cache interruption or the application dies unexpectedly, all the entries in the cache are flushed to the OSDs so that you can manually flush the data and then invalidate the cache.