Hi all, Kyle was telling me that some of the MySQL folks were interested in doing an InnoDB backend that sat directly on librados. This is pretty interesting for DBaaS use-cases, but it reminded me that the MyRocks stuff that Facebook has been doing (a RocksDB backend ofr MySQL) has also been showing a lot of promise, and that someone had told me that some CMU students had written a librados backend for either leveldb or rocksdb. Perhaps doing a RocksDB backend will work just as well (or better) for the mysql users *and* whatever other things are using rocksdb out there. It turns out that writing a new backend is really not that hard. I had to do one for BlueStore and it didn't take that long, and most of the work was building BlueFS, a toy file system that sat directly on a block device. In the librados case, we can make a super-simple directory structure in omap and write files to individual rados objects. Writes are always streaming and full object writes, nothing is read until it is written, and so forth. I think it could be done with a few days' effort. Also, as part of the bluefs work, I pushed an EnvMirror backend upstream that tells rocksdb to mirror to two backends and validate that the return identical results on all reads. This was super useful for debugging the bluefs/bluestore backend, and would aid testing here, too. Anyway, if anyone thinks this is a good or bad idea, or is interested in working on it, let us know! sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
