What Are Software-Defined Data Centers, Networks, and Storage?

The software defined data center (SDDC) is a natural evolution of virtualization, extending it beyond virtual machines on a server to virtual networks, virtual storage, and new automated management tools with similar benefits to traditional virtualization. The term was first coined by VMware CTO Steve Herrod in 2012.

In an SDCC, all physical infrastructure is treated as one resource that can be divided as needed, rather than split up by individual servers, switches, routers, hard drive, storage bays, and so on. Software and services are installed on an abstracted layer on top of data center hardware to manage virtual networks, virtualized servers, and virtual storage.

All of this allows integrated and attached security and network settings for each virtual machine, and the simplified management also makes tasks like backup, archive, and application deployment much faster. Software defined infrastructure further increases efficient use of available resources, increasing utilization of physical hardware and reducing both capital and operational expense.

In a software defined data center, customers can self-provision a virtual data center, specifying their required resources, network devices, and storage. The management of physical infrastructure will come from policy-driven software, defined by data center operators in accordance with service level agreements (SLAs).

Image source: VMware

Software Defined Networks

Software defined networking (SDN) uses software to manage all network devices as a single resource, allowing load balancing, firewalls, VPN, and more to be attached to individual virtual machines. These settings then move with the virtual machine as it communicates via the network. The virtual components are “logical” rather than physical: when two VMs are connected through a logical switch, the data transferred between them must filter through these rules before crossing the physical network.

SDN decouples the control system that sends data packets from servers and decides which data packets to accept from the data system that physically transfers the packets. The physical location of network devices no longer defines network activity. Instead software controls network settings and can be placed anywhere, on any server. Each virtual network is isolated from other networks and the physical hardware, and there can practically be an infinite number of them, limited only by the resources of the server on which they are hosted and the network infrastructure through which traffic must pass.

SDN supports overlapping IP addresses, which is ideal for testing and development, as individual security and network settings do not need to be set up and configured for each stage of the development and testing process. These settings were previously programmed into physical hardware – switches and routers.

Software Defined Storage

Software defined storage (SDS), much like SDN, treats the available pool of storage resources (often a storage area network (SAN) of fast, connected storage devices) as a single resource rather than individual drives and arrays. Management software then allows smart provisioning of storage on-demand by virtual machines. With virtualized storage, systems from multiple vendors can be managed as a single unit.

Automation and Management Possibilities

The software defined data center enables new possibilities for flexible, on-demand provisioning of virtual infrastructure. Users can launch pooled resources customized to specific application requirements, while overlapping hardware is utilized nearer to 100% of its capabilities. Every virtual network launched by a customer would exist in the same data center, but have its own security, firewall, and authentication requirements.

When combined with data center infrastructure management software and protocols (DCIM), an SDCC can be much more efficiently managed. As customers provision their own data centers, automatic rules control what resources are used when, and everything is tracked and monitored for granular insight and control. The bottom line? Less downtime, more energy savings, and more resources available.

Further reading:
http://www.wired.com/insights/2013/05/software-defined-data-centers-whats-the-buzz-all-about/
http://www.infoworld.com/t/data-center/what-the-software-defined-data-center-really-means-199930

Posted By: Joe Kozlowicz