Infrastructure Software

I am currently in the process of an evaluation. We are planning to run an OpenVZ Cluster (true hypervisors have too much latency/overhead for the required scenario) with a shared storage for all participating nodes.

The OpenVZ containers will be stored on the shared filesystem. Use case is mostly reads (executing one binary in each container, which may load bulk data into memory from the shared fs as well), practically no writes. Since every process will run in its own OpenVZ container directory, there will be no concurrent reads/writes (ie locking should not be much of an issue). There might be > 200 node clients, each node might have up to 20 openvz containers (though since these use the node FS this should not matter). We want to use a central and cheap storage (no distributed storage).

Since OpenVZ is RHEL based i am considering Oracle Linux (i assume the OpenVZ RHEL 6.x based Kernel will run without issues on Oracle Linux). Now considering the shared filesystem i could use NFS or OCFS2 on top of iSCSI (linux software based) over Ethernet. I read a few performance benchmarks, in which OCFS2 comes out on top due to a more scalable design. However i am not sure whether these benchmarks are all that relevant to my use case, since they take into account more "normal file system usage". NFS is a lot easier to setup and to maintain, however if OCFS2 performs and scales significantly better for my use case i would give it a try.

I would appreciate all input, since i assume there are quite a few people out there who are more knowledgeable with such use cases and OCFS2 in particular.