Recently I have made some progress in storage virtualization based on thin block size over RAID. The next step is to migrate that part into SAN Dual-controller. Software running in controller is quite different from one running in server
with just one controller. There are many limitation about memory, buffer. And the aim of automatic tiered storage is to make the ILM&DLM easier, not making trouble to cause system collapse.
It's very difficult to find software running in dual-controller in the open source, I have the plan to release that part with LGPL license.