We are looking to implement a new SAN, either an EMC CX400 or an HP EVA 6400. In either case we are considering a storage pool technology. EMC calls it virtual provisioning and I believe HP calls it storage pooling. Essentially you have one or two large pools of drives and from there your SQL Server installations are presented logical chunks of disk. It's even possible to have multiple arrays on the same drives. In HPs proposal we will have a pool of (58) 146GB drives. We can then present them to SQL Server as one drive letter or multiple drive letters.
We are still trying to understand how this technology works. It clashes with the old practice of keeping your logs, data and tempdb on separate arrays in order to minimize seek time.
We would love to hear from people who are using this technology. How well does it work for you? How big is your storage pool and did you carve it up into logical drive letters? Do you still use Perfmon to monitor disk performance? What problems does this present?