[komljen]

Correct, Ceph is much larger than the file system. As I said at beginning of article I'm using each Ceph component, RBD, RadosGW and CephFS and I will write article for each of that. This is just some sort of getting started guide. I'm interested at running Hadoop on top of CephFS, is it stable enough?

[noahdesu]

The instability we have seen is with the metadata server, but have been able to relatively quickly push fixes to upstream as we encounter them. The focus has been on stability, and we have been running pretty large terasort jobs without issue. In the upcoming release of Cuttlefish, due out any time now, there will be locality information exposed to Hadoop for better task scheduling. We will start focusing on improving Hadoop performance soon, now that things have stabilized.