We are trying to ascertain the WAF incurred by the file system when running rocksDB. This is different from RocksDB WAF because we ignore the amount of key/value pairs and take the ratio between what comes out of Positioned{Append} and the bytes that arrive to the device (Calculate that with smart log). Since we are interested in write amplification we use the fillrandom and overwrite benchmarks, we make sure we use_direct_io. We precondition the Filesystem by filling it up to 90% capacity and then run db_bench up to 97% capacity.
Has anyone every measured this for XFS?
I’m getting a 1.005 WAF which seems a bit low. With the FS being pushed to the limit I was expecting something close to 1.7.