I have a server running with wiredTiger storage engine, but without compression enabled globally. Now I want to change the "block_compressor" option for a single collection to use "snappy". According to the mongoDB documentation this is possible while creating a new collection using "db.createCollection()", but how can I perform this step for an existing one? (Maybe for new replica set members before initial sync)
Since initial sync between non-wiredTiger and wiredTiger members in a replica set is performed on a per-document level (and not by copying the files), this should be possible...
http://docs.mongodb.org/manual/reference/method/db.createCollection/#specify-storage-engine-options