Pay Attention 007...

Sometimes things you should spot just pass you by when you're not paying attention. So it is for me with N-Port ID Virtualisation. Taking a step back; mainframes had virtualisation in the early 90s. EMIF (ESCON Multi-Image Facility) allowed a single physical connection to be virtualised and shared across multiple LPARs (domains). When I was working on Sun multi-domain machines a few years ago, I was disappointed to see I/O boards couldn't share their devices between domains, so each domain needed dedicated physical HBAs. More recently I've been looking at having large servers with lots of storage using a data and tape connection - hopefully through the same physical connection, but other than using dual port HBAs, it wasn't easily possible without compromising quality of service. Dual port HBAs don't really solve the problems because I still have to pay for extra ports on the SAN.

Now Emulex have announced their support of N-Port ID Virtualisation (NPIV). See the detail here http://www.emulex.com/press/2006/0918-01.html. So what does it mean? For the uninitiated, when a fibre channel device logs into a SAN, it registers its physical address (WWN, World Wide Name) and requests a node ID. This ID is used to zone HBAs to target storage devices. NPIV allows a single HBA to request more than one node ID. This means if the server supports virtual domains (like VMware, XEN, or MS Virtual Server) then each domain can have a unique WWN and be zoned (protected separately). Also this potentially solves my disk/tape issue allowing me to have multiple data types through the same physical interface. Tie this with virtual SANs (like Cisco VSANs) and I can put quality of service onto each traffic type at the VSAN level. Voila!

I can't wait to see the first implementation; I really hope it does what it says on the tin.