The new, energy-efficient HP DL380 G7  server combined with VMware vSphere 4.0 virtualization software can produce extraordinary power savings, compared with an older server running a single operating system. Even compared with a 3-year-old server running an older version of VMware, the savings achieved with the DL380/vSphere combination can be substantial.
These two products together produce a synergistic effect that multiplies power savings. For instance, a mostly idle system can automatically power down unused processor cores to reduce power consumption during off-peak hours, while Intel’s Turbo Boost and Quick Path technologies produce higher performance when needed, allowing a greater number of virtual machines (VMs) to run on a single system. The systems themselves are also more efficient: The power supplies are 92 percent efficient or better, and the standard Xeon 5600 series CPUs and 2.5-inch hard drives use substantially less power than older components.
In addition, vSphere adds several new features to the list of power-saving capabilities, including the ability to over-provision memory, which means that a smaller, more energy-efficient server can still run many VMs without running out of RAM. In a clustered environment, VMware Distributed Power Management can automatically move active VMs to a single server and shut down unused systems when loads are low, then reactivate the servers and move VMs to ensure optimum performance during peak loads.
For this review, HP supplied a DL380 G7 equipped with two Xeon X5680 six-core 3.33 gigahertz processors; 24 gigabytes of RAM; 2x 1-Gigabit Ethernet ports; RAID controller; six 2.5-inch 300GB SAS hard drives; and two 750-watt power supplies. Despite the maxed out configuration, the system drew less power and was quieter than an older DL360 G4 with two 3.4GHz Xeon CPUs (two single-core CPUs), 8GB RAM and two 36GB hard drives. I could load and run 20 VMs on the DL380 G7 with no performance degradation.
The ability to consolidate many physical servers into a single system  — or run more VMs than older hardware can accommodate — and at the same time save on energy costs is a win-win for IT departments. Management costs go down, energy costs go down and performance goes up. And you can start off with a relatively inexpensive server configuration of one two-core CPU, 4GB RAM and one hard drive, and expand it to as many as 12 cores, 192GB RAM and eight drives.
The percentage of savings on energy costs an IT department can achieve by updating from a 3-year-old server to a new Energy Star–qualified server
Installing VMware on the HP is easy, mainly because HP  is a vendor partner with VMware . This close relationship means that hardware combinations are pre-certified to work with VMware, and VMware tech support can readily address any problems without worrying about whether all the hardware in a system is compatible. In addition, HP ProLiant servers have many features to enhance reliability, including error-correcting, mirrored or hot-spare RAM, 32 sensors to monitor every aspect of server functioning, dual redundant power supplies and integrated lights-out monitoring and management.
The vSphere software also offers substantial reliability features, including vMotion clustering, which can automatically move VMs from one hardware server to another in case of failure.
Cost can be a factor. Replacing servers for the power savings alone will not pay off — the cost of a new server is greater than the power savings realized over the life of the server. However, most organizations replace their servers on a cycle of two to five years; when the old servers are replaced with new, high-performance machines, the power savings are a bonus.