For example, Thanatos -- the server that ran the company’s medical reimbursement and benefit management software -- was a dual-socket, single-core Intel Pentium 4 running at 2.8GHz whose load averaged at 4 percent. Meanwhile, Hermes, the voicemail system, ran on a dual-socket, dual-core AMD Opteron 275 system running at 2.2GHz with an average load of 12 percent. Not only were these two completely different processor architectures, but Hermes had twice as many processor cores as Thanatos. Making things even more complicated, processor utilization wasn’t the only basic resource that had to be considered; memory, disk, and network utilization were clearly just as important when planning a virtualized infrastructure.
Eric quickly learned that this was why there were so many applications available for performing capacity evaluations. If he had only 10 or 20 servers to consider, it might be easier and less expensive to crack open Excel and analyze it himself. He could have virtualized the loads incrementally and seen what the real-world utilization was, but he knew the inherent budgetary uncertainty wouldn’t appeal to CEO Bob Tersitan and CFO Craig Windham.
So, after doing some research, Eric suggested to Brad that they bring in an outside consulting company to do the capacity planning. Eric asked a local VMware partner to perform the evaluation, only to be told that the process would take a month or two to complete. The consultants said it was impossible to provide a complete, accurate server utilization analysis without watching the servers for at least a month. Otherwise, the analysis would fail to reflect the load of processes that were not always active, such as week and month-end report runs.
That delay made good technical sense, but it did mean Eric and Brad couldn’t meet Bob’s deadline for the implementation proposal. Fortunately, Craig was pleased that an attempt to make the proposal as accurate as possible was being made and his support eventually made Bob comfortable with the delay.
The delay turned out to be good for Eric and Bob, as there were many other planning tasks that hadn’t even come close to completion yet, such as choosing the hardware and software on which they’d run the system. This analysis period would give them breathing room to work and try to figure out what they didn’t know.
When the initial capacity planning analysis did arrive some time later, it showed that most of Fergenschmeir’s applications servers were running at or below 10 percent equalized capacity, allowing for significant consolidation of the expected 72 server deployments. A sensible configuration would require eight or nine dual-socket, quad-core ESX hosts to comfortably host the existing applications, leave some room for growth, and support the failure of a single host with limited downtime.