Capacity Planning – Friend or Foe?
A systems administrator has a big job. The job description for systems administration seems to take in just about anything management can think up. At the same time, systems administrators become very possessive of the systems they care for because every aspect of the operation of those systems is their job.
In many ways, systems administrators are the real backbone of the computer industry. It can be a thankless job but it is one that a true systems administrator can be proud of. You work hard, you know your systems inside and out and you keep them running, which keeps the company running. It’s a big job but you are up to the task.
Perhaps because systems administrators are held accountable for the functioning of their systems, it is easy to become defensive when part of your job is taken away by a subset of the discipline that seems to be unnecessary. Capacity planning seems to seek to take away part of your job as a systems administrator. Professional capacity planners are very aware of the perceived threat that they pose to systems administration personnel.
But that tension does not need to be there because capacity planning can be the best thing that ever happened to a systems administrator. Not only can a well developed capacity planning program take some of the stress off of the job of systems administration, it can help you justify upgrades and manage workloads because of the wealth of solid statistical information that good capacity planners can provide.
Capacity Planning Defined
Capacity planning is an IT discipline that is not well understood. The title of the office is well chosen because the goal of a professional capacity planner is to help measure the performance of computer system to determine how much of the capacity has been used and if the capacity of the system is being well used. The way capacity planners accomplish this goal is through statistical analysis and forecasting. Detailed metrics about the performance of the computer systems and the applications being executed within a computer system are gathered by software modules that constantly collect these metrics and store them at a database level for evaluation.
The result are highly reliable models and statistical graphs that depict the capacity of a system on an hourly basis. This is not opinion being graphed to accomplish the goals of a particular department. A well developed capacity planning department is above the goals of managers or even the objectives or budget of the company. The goals of capacity planning is to forecast when a computer system will need additional capacity and to help balance the load of computer systems when excess capacity is identified.
Friend Not Foe
Before capacity planning was defined as a separate discipline from systems administrators, the determination when a computer system was approaching capacity was done by the systems administration group. Very often, this determination was done by "gut feel". When you are responsible for the operation of a computer or a system of computers, you develop a feel for when the system is operating well and when it is bogged down. You know the workloads that you are putting on a computer system and the kind of internal demands each workload requires to complete the work to be done.
But too often, when a systems administrator goes to management to request more capacity for a system under his or her charge, that request is not received well. Management may see the systems administrator as ambitious or unaware of the budget constraints of the business. This is not the case but that is a perception that sometimes keeps systems administrators from being effective at providing systems that are adequate to the demands of the business now and certain to be capable of dealing with any growth planned for those systems in the future.
Capacity planning can give systems administrators the "teeth" it takes to graphically demonstrate that the capacity of the systems being used may become critical in a specific time frame based on projected use and growth. Through graphic representation of existing usage and capacity and forecast models of when a system will exceed capacity, a good capacity planning program can get out ahead of a potential crisis level capacity shortage long before it happens.
As a systems administrator, you know that you must begin to plan a systems upgrade long before you hit maximum capacity for your systems. In fact, if you are hitting above 70% utilization for any critical processing time frame, you are at capacity and any increase in demand could represent a capacity crisis that could cause the systems the company depends on to fail to deliver as expected.
This concept is sometimes hard to get across to the business level of management who are often a little stingy with buying more computer capacity based on the word of a systems administrator. Capacity planning can give you statistical "proof" that a crisis is coming where the company will need computer support to accomplish its goals and that systems availability simply will not be there. When capacity planning can provide evidence that you need that for the company to continue to grow and prosper, it must make an investment in computer power, that benefits systems administrators by giving them what they need to do their jobs.
In addition to proving or disproving that systems being used require additional horsepower, capacity planning can be an invaluable aid in load balancing. Often a large business may operate many midrange or large computer systems and each of them have mission critical workloads that are automatically executed throughout the week. Capacity planning can measure when maximum capacity is being used and the amount of resource each application is consuming.
Applications often reserve a lot of resource capacity when they launch and then release some of that resource as they process their workload. This means that very often a system that seems to be exceeding capacity and in need of an upgrade could benefit by targeted load balancing. Capacity planning measurement can pinpoint how to do that load balancing. By staggering when resource heavy applications start, you can often put a lot more work through a system without stressing the capacity of the unit because the jobs use and release their resources in cooperation with each other. This is smart systems management and it is made possible when systems administrators are given the help of capacity planning measurement and reporting.
Systems administrators should see capacity planning help as an ally in providing the best support for systems performance. Capacity planning does not seek to take away the authority or the decision making of systems administration experts. Instead, capacity planning can support and make better the job of systems administration.
When the two functions work together as partners, each succeeds. But the ultimate winner is the business because it gets the best out of their computing resources. In addition, the business has the assurance that when a capacity shortage looms, they will have plenty of time to prepare for it because they had the help of solid systems administration and expert capacity planners working together.
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