By Manon Buettner
If you are interested in offering infrastructure-as-a-service (IaaS) to your customers, then you need to know about virtual data centers (VDCs). VDCs are populated by totally user-defined quantities of virtual resources as opposed to the traditional physical hardware in a colocation or on-premises data center. This includes servers, storage, switches, routers, firewalls, graphics cards and other hardware elements. Users define how much compute, storage, network and security they need to execute all cloud-intended applications and the provider provisions resource pools accordingly.
VDCs can be implemented as:
- private, where one or more of the physical infrastructure elements is dedicated to one customer before being virtualized
- public where all elements of the VDC are shared between multiple customers
- hybrid where a customer tethers an on-premises or colocation data center to their VDC
In a virtual data center, the user-defined server or “compute" resources from the physical device are virtualized, broken into two resource pools — memory (vRAM) and processors (vCPU) — and added to the management portal. Customers then use the resource pools to power business applications by creating virtual servers (VMs), complete with operating system and application software, and then assigning the necessary storage type/amount to ensure proper performance and data retention.
This is different from the cloud industry norm where customers purchase compute resources by the VM or cloud server, normally defined with a specific vCPU x vRAM parameter (e.g., 2x8). This is fine if one’s needs are exactly 2x8, but if they are less/more, users end up having to choose whether to overprovision or underprovision when deploying an application. VDC compute resource pools allow users to map whatever number of vRAM and vCPU they want to a given VM, minimizing waste and optimizing the application with its ideal resource pool.
It is possible to cluster virtual servers (vApp), assign IPv4/IPv6 addresses and other common activities associated with physical servers.
An on-premises data center will feature storage devices, many of the medium to large companies featuring storage area network (SAN) capabilities complete with controllers, SAS, SATA and SSD drives. Infrastructure managers will connect the SAN to the corporate network and allow employees to use it as a central data repository. Typical vendors include NetApp, EMC, HP and Hitachi Data Systems (HDS) among others.