The capacity management process (Mind the Gap series 3 of 10)

The above is as detailed as ITIL gets in describing the capacity management process, subprocesses and activities. It presents a useful summary of the main activities and presents them at three levels being the resource or component level, the service and business levels. It’s a neat overview and shows the essential nature of the capacity database and capacity management information system at the heart of the process. It is a key part of the 50 pages or so that describe the capacity management process in ITIL. The same topic is also discussed in ISO/IEC 20000 but summarized to just a few pages.

This shows the spectrum of implementation of ITSM and capacity management within it

across sites.

There are levels of process maturity suggested which correspond roughly to typical levels of ITIL implementation. However, for any one application, it may move from one level to another during its life cycle – which on average is only around 18 months.

Thus, at the start, it may be subjected to intense performance engineering and QA trials to derive resource requirements. But once it has settled down it may well be little monitored, or perhaps simple utilization trends maintained.

Also, for any site, given limited resources, it's likely that decisions will be made to go further up the maturity grid for servers that are expensive (mainframes and super-servers) and for services that are mission critical. Hence there is a “curly bracket” indicating that most sites will choose to monitor all servers and services, but only trend significant services and only model expensive servers.

My experience is that the higher up the grid that curly bracket is implemented, the higher is the regard for IT within the company and its perception externally. These are important considerations for a CIO whose life cycle on average is also around 18 months… so he or she is likely to be very interested in a gap analysis of what is actually going on in their capacity management domain.

On Wednesday I’ll be taking a look at the procedures for gap analysis.

Adam Grummitt

Distinguished Engineer