Vblocks are bundled virtual machine, server and storage packages marketed by the Virtual Computing Environment (VCE) Coalition, which comprises VMware, Cisco and EMC. Vblock bundles come as Vblock 0 (300 to 800 VMs), Vblock 1 (800 to 3,000 VMs) and Vblock 2 (3,000 to 6,000-plus VMs) and are made up of Cisco UCS servers, Cisco Nexus and MDS fabric switches; and EMC Clariion or Symmetrix storage arrays.
VCE’s Vblocks come in three configurations — Vblock 0 (for 300 to 800 VMs with EMC Celerra storage), Vblock 1 (for 800 to 3,000 VMs with Celerra or Clariion storage) and Vblock 2 (for 3,000 to 6,000-plus VMs with Symmetrix storage).
Vblocks 0, 1 and 2 each have completely different EMC storage subsystems that can’t talk to each other, are not interchangeable and you can’t scale through them.
For more details related to Vblock architecture, please see http://www.vce.com/asset/documents/infrastructure-platforms.pdf