Wednesday, October 2, 2013

Virtualization and Shared Storage

When Interwest’s current technology upgrade was in the planning stage it quickly became apparent that, in order to provide new and improved resources to our staff and customers, as well implement an infrastructure that would scale as our needs grew, a better approach was needed.  Traditionally, a new physical server was added each time a new resource was needed.  With initial planning for five to seven new servers, the cost and space requirements would extend beyond the constraints of the budget and current data center rack space.


The Solution

Virtualization and shared storage

Virtualization allows one physical server to host multiple software or virtual servers.  These virtual servers function as individual servers, as if they were standalone physical servers, but they do not consume the space or energy of individual physical servers.

Shared storage allows multiple physical host servers to ‘share’ the virtual servers.  If a physical host server needs to be taken offline for maintenance, the virtual server can just be moved to another host without any downtime to the virtual server or its resources.


Interwest’s Implementation

After much research and hands-on testing, Interwest decided to implement two Citrix XenServer virtual hosts and an internally redundant, dual-controller NetApp Storage Area Network for shared storage to cover the initial five to seven virtual servers.

The Citrix XenServer hosts work together with the NetApp shared storage to provide redundant availability to the virtual servers they host.  The NetApp SAN has redundant controllers with their own redundant disks and redundant power supplies.

The solution scales well.  Adding one additional XenServer host has allowed the number of virtual servers to increase to 14 while maintaining the same level of redundancy. Three XenServers and one NetApp can replace 14 physical servers.




Advantages of Virtualization

The benefits of virtualization are numerous…a few key benefits are:
  • more efficient use of resources, including CPUs, memory and storage
  •  decreased energy consumption and space requirements
  • easier server management
  • fewer physical servers on which to maintain warranties


Advantages of Shared Storage

The benefits of shared storage are numerous…a few key benefits are:
  • increased resource availability
  •  more efficient storage via thin provisioning