Storage Virtualization

Storage Virtualization

Introduction: Topic of the Article is Virtualization. Articles approach is Informational. In 2005, Virtualization is the technology that took hold in the Enterprise. Virtualization is software that allows a piece of hardware to run multiple operating system images at once. The software moved from test and development and into the data center faster than anyone imagined, including the experts. And while there are sure to be some bumps in the road in 2006 as the technology moves from awareness to adoption, you can bet most IT pros will be running virtualization in the data center before the end of next year.

Major Reasons (points) for the need of Virtualization: On average, servers have a utilization rate of only 5% to 10% and utilization is decreasing as more powerful servers proliferate. Although servers sit idle most of the time, organizations continue to purchase more of them in order to provide an isolated operating environment for each new application. Additional servers are included in the data center for testing and clustering and as disaster recovery centers. The cost of this server extravagance is substantial. In addition to the purchase price and set-up expense, each server consumes floor space, requires ongoing maintenance and needs to be upgraded as the hardware becomes obsolete. Most important is the daily cost of electricity, which is included in the overhead -- and each server consumes lots of electricity. The amount of electricity used, of course, depends upon the server. An efficient low-end server might use as little as 200 watts an hour, while a newer, more powerful server can consume 450 watts. Older servers can use well over 500 watts

This cost alone should be enough to prove my point, but that's not the end of the story. The actual cost is roughly double that amount due to the electricity required to counteract the heat generated by servers and other data center equipment. Failure to adequately dissipate server heat results in the reduced lifetime of its parts, increased downtime and, possibly server failure. It requires an equivalent amount of electricity to cool servers as it does to power the servers.

It doesn't stop there. PDUs, generators and additional circuits are required in order to accommodate the ever-growing number of servers. Using some rounded numbers, total energy costs can be estimated at between $50 and $100 per server per month.

Making a change with virtualization: A basic advantage of virtualization is the ability to run multiple jobs gracefully on a single server, a consolidation that cuts administrative expense and electricity bills. At a higher level, it permits computer systems to become more responsive to changing work priorities or hardware problems. Virtualization changes the data center dynamic by allowing many virtual servers to share physical hardware. Virtualization software packages -- manufactured by companies such as VMware, XenSource and Microsoft -- enable much more efficient use of x86 servers, meaning multiple operating systems can run on a single physical server. Virtual servers are guaranteed specific amounts of processor cycles, memory access, disk I/O and network bandwidth. The number of virtual machines that can be consolidated onto a physical server depends on the characteristics of the original machine and the server host. Servers, in effect, become like drives in a disk array. Network administrators no longer need to be concerned about individual physical servers any more than they focus on individual hard drives.

Another benefit of virtualization is automatic transfer of virtual machines from a failed physical server to other physical servers that have adequate resources. Disaster recovery centers also benefit from consolidation; under virtualization, the disaster recovery center requires far fewer physical servers to provide recovery for numerous virtual machines. Even without considering costs, the benefits of virtualization -- such as high availability and improved disaster recovery -- present a compelling story. Fortunately, the economic benefits of virtualization are substantial as well. Consider, for example, a data center populated with a mix of old and new servers of varying configurations with an estimated average total energy cost per month of $75 each. If the organization consolidates 100 physical servers onto six new two-CPU dual core servers, the net electric/power savings for the 94 virtualized servers comes to approximately $423,000 over five years. If the organization pays $6,000 for each physical server (including tax, shipping and set-up) and commonly refreshes servers once every five years, then additional savings of approximately $560,000 are realized over a five-year period for 94 servers that don't need to be replaced. This is a combined savings over five years of almost $1 million.