[armon]

To reiterate a bit on what hardwaresofton has already said, yes you could use Cassandra. However, Cassandra like ZooKeeper is just a building block. It doesn't actually provide service discovery, health checking, etc. You could use it to build all of those, but it doesn't provide it.

We compare Consul to ZooKeeper here, but much of that applies to Cassandra as well: http://www.consul.io/intro/vs/zookeeper.html

Internally, Consul could also use something like Cassandra to store the data. However we use LMDB which is an embedded database to avoid an expensive context switch out of the process to serve requests with lower latency and higher throughput.

[opendais]

This is more of a wishlist item in my professional life. I'm not trying to dispute the choice you made which is to add an additional type of critical cluster for persistence purposes, since that is how all of such services I've seen so far are designed.

I just wish I could avoid having to maintain Cluster Type A for service discovery and Cluster Type B for data storage.

[simonw]

I hadn't seen LMDB before. How does it compare to LevelDB? On first glance it looks like the two have similar characteristics.

[hardwaresofton]

Check out LMDB's page:

http://symas.com/mdb/

I dunno if leveldb supports acid now (or recently came to), but that's a big difference