We're using RocksDB as a persistent Kafka state store for compacted topics and need to be able to estimate the maximum disk space required.
We're using the default config. settings provided by Kafka, which include Universal compaction, no compression, and 4k block size. Given these settings and a topic w/ key size K, value size V, and number of records R, I'd assume a rough disk space estimation would be of the form max. disk space = (K+V)*R*M*2 where M is an unknown DB size -> disk size multiplier and *2 is to allow for full compaction as per here <https://github.com/facebook/rocksdb/wiki/Universal-Compaction>. Does this look right, and can anyone provide a ballpark range for the multiplier M and/or some guidelines for how to estimate it? much thanks, Chris
