Data center interconnects are generating a lot of news at EMC World this week. You have a startup like Infineta Systems coming out of stealth mode to demonstrate its Velocity Dedupe Engine, The product is meant to reduce the amount of bandwidth data replication (both synchronous and asynchronous) consumes by a factor of ten.
Meanwhile, EMC introduced VPLEX, a family of “private cloud” appliances. VPLEX also promises accelerated data replication and flips the model of traditional replication on its head by making replicated data active at two sites simultaneously, rather than having a primary site and backup site. But VPLEX also promises to enable virtual machine migration across data center interconnects.
Live virtual machine migration across data centers came up often at last month’s Interop Las Vegas. Everyone wants to do it, but no one seemed to think it was a practical reality yet. For one thing, latency sensitive applications can be derailed if a live VM migration from one data center to another takes a few milliseconds too long. For another thing, VMware’s vMotion technology only supports virtual machine migration across Layer 2 connections and a great many enterprise WANs are Layer 3 networks. Cisco Systems introduced Overlay Transport Virtualization a few months ago, as a way to create a “virtual” Layer 2 connection between WAN links in order to enable vMotion migration across data centers.
Now EMC’s VPLEX promises to virtualize storage resources across data centers so that a virtual machine and its resident application can migrate from one data center to another and without having its access data interrupted. It can access the data locally no matter what its geographic location is. Enterprise Strategy Group has validated this technology across a 100 kilometer WAN link (PDF). If storage can be federated across data centers like this, it could improve the performance of live migration of VMs.