Performance & Capacity Articles
Capacitas recognises the importance of staying abreast of changes in technology and best practice and is committed to a programme of research to support the capacity planning community. Capacitas releases several whitepapers and commentary articles per year, which are made available to our customers via this web site.Capacity and Performance Management Primer
This article provides a short introduction to the role of capacity and performance management.Meeting the Challenges of Capacity Management in Virtualised Environments
In recent years, the increased popularity of server virtualisation has introduced considerable complexity into the Capacity Management process. This article is an abridged version of a Capacitas whitepaper, available here, that describes possible solutions to some of the challenges that may be encountered when conducting capacity management of services based on server virtualisation technologies. The paper also reveals a number of important areas where virtualisation is not able to deliver the magnitude of cost savings that many organisations initially expect.Capacity Management Assessments: The need for a baseline
(or: How do you know where you’re going if you don’t know where you are?)
ITIL, now in version three, recommends a Continual Service Improvement Plan or CSIP for services and processes. The Capacity Management process is one such process that can be strengthened by such a plan. Before any improvements can be made to an existing process or service it is important to understand what the target is and more importantly where one starts from. This article shows two methods that will allow a Capacity Management department to undertake a review of its current status and compare that to its target, other Capacity Management departments, its own previous performance or best practice.
IBM Mainframe Capacity and Performance Management
It is often said that the discipline of Capacity and Performance Management (CPM), along with other traditional service management processes, grew out of the management of the IBM Mainframe. This may or may not be true; however, this article looks at what sets this platform aside from others from a CPM viewpoint, instrumentation and workload management.Microsoft Excel – The Capacity Planners’ Tool of Choice
When one attends IT industry user groups, e.g. UKCMG, the choice of software tools can be bewildering and the costs associated with them potentially prohibitive. Fortunately Microsoft Excel can be used for the analytical, automation and presentation tasks that make up the majority of the CPM practitioner's working day.Interview with Andy Bolton on Capacity Planning Tools
Andy Bolton, Chief Executive Officer, Capacitas, was interviewed by Drew Robb, freelance journalist in 2004, for Building a Model Infrastructure published in ComputerWorld. Material was also used for Capacity Planning: Art, Science or Magic published on EarthWeb.Book Review - Achieving ISO/IEC 20000 Capacity management
This article contains a review of the book Achieving ISO/IEC 20000 Capacity management by Jenny Dugmore and Shirley Lacy.A Ten-Step Plan to Effective Capacity Management
Designing and building an effective capacity management function has never been harder: the competition for talented staff is high, as is the current workload of projects and 'business-as-usual'. At the same time salary and training budgets are often constrained. How does the contemporary capacity manager cope with these challenges? Follow our ten-step plan to designing and building an effective capacity management function; wherever your starting point and whatever your challenges you will find useful techniques in this article.The Data Centre Power and Space Challenge: Are Virtualisation & Consolidation Effective Solutions?
The steady growth of distributed computing since 1980 has widened dramatically the ownership and use of information systems compared to the mainframe and minicomputer era. The trend toward decentralised computing has created new issues with accommodating large numbers of Unix or Windows servers, including:
- the increased resource requirements for managing and maintaining the estate
- the increased rack, floor-space and cabling requirements
- the wide distribution of locally attached disks
- the subsequent power delivery and cooling requirements, a growing environmental concern
Prioritising Capacity Management Resources
Capacity Management is a vital and integral function to any successful IT organisation. In an ideal world all IT services would be capacity managed throughout their lifecycle. However in a medium to large organisation it is not possible to spend the required amount of time on each service that the business user would often like, although when offered the choice to pay for their desired level of capacity management they usually decline. This mismatch of demand for, and supply of, capacity management services is an intriguing issue for a capacity manager to deal with, for it is his de facto role; therefore the way he deals with this problem can, to the business user, be indicative of his skills as a Capacity Manager.When and why to use Simulation Modelling?
Capacity and performance engineers often want to predict the response times of applications over ICT systems. Modelling techniques can help capacity and performance engineers achieve this. However, there are different modelling techniques that can be used. ITIL defines the main modelling approaches as trending, baselining, analytical and simulation. This article lists some of the reasons that you might want to consider using discrete event simulation modelling to predict the performance of your ICT system.Web Performance Tips
The rise of web services, particularly as revenue collection systems, means that web service performance is becoming increasingly important. There are a number of reasons why it is often difficult to ensure that web services meet SLAs:- Service demand may be difficult to predict
- Service demand may be extremely bursty, i.e. large numbers of requests may arrive in a short space of time
- The web service is underpinned by a complex infrastructure, consisting of multiple technology layers
Getting the most from Performance Testing
Capacitas believes that analysis of performance testing results should be carried out in conjunction with analytical performance modelling. This has helped Capacitas identify performance problems in the past that wouldn't have been observed by looking at response time results in isolation. The overhead of performing analytical modelling is relatively small compared to the overhead of carrying out the performance tests. The author has developed a set of tips that will help you achieve the maximum benefit from your performance testing process.Negotiating Performance SLAs
The SLA for response times should be clear and measurable to both parties. In the same way a customer purchases a car from a dealership he understands the specification of the car e.g. its maximum speed. The tips contained within this article list some of the things that are useful to define during contract negotiations in order to avoid subsequent disagreements.The Differences between Performance Engineering and Capacity Planning
The capacity planning and performance engineering functions have many common techniques and skill sets. As a result, the distinctions between these two closely related functions are often misunderstood. This article outlines 10 key differences between performance engineering and capacity planning.Conducting Workload Characterisation
Although it is not mentioned in the ITIL Best Practice for Service Delivery book, workload characterisation is a key Capacity Management discipline. Workload characterisation is the method by which the total resource utilisation is broken down into groups of resource consumers, or workloads. Each workload represents some meaningful group of applications, processes or set of users, and may be related to a business process or activity.Windows Capacity and Performance Monitoring Overview
Microsoft provides access to a vast array of capacity and performance monitoring counters. These can be monitored through a bundled tool named System Monitor (Sysmon) or through a multitude of third-party tools. The sheer number of counters is often daunting to the uninitiated. This article provides a simple introduction to Windows performance monitoring and a basic set of meaningful performance counters to be monitored on any server.Understanding 'Percentage Waiting for I/O'
Various operating systems have monitoring tools that report values for Percentage Waiting for I/O. Whilst this is not a new metric, there is often confusion surrounding the meaning and interpretation of this statistic. This article explains why Percentage Waiting for I/O is not a useful metric when considering the performance of the disk I/O subsystem.Importing W3C Web Server Log Files using Microsoft Excel Visual Basic for Applications
Excel is probably the most important commonly-available analysis tool for IT professionals. Visual Basic for Applications can be used to extend the functionality of Excel to support common performance and capacity management activities. This article explains an add-in that is used to import W3C web server log files for analysis using Excel. The add-in allows the user to select a file, which is then opened and automatically edited to ensure that unnecessary and repeated headers are removed.Microsoft Excel 2007 for Performance and Capacity Management
This article reviews Microsoft Excel 2007 Beta 2, explaining how the key changes will impact performance and capacity management professionals:- User interface redesign, with menus and toolbars being replaced by Ribbons
- Number of columns per worksheet increased
- Number of rows per worksheet increased
- Pivot Tables
- Improved scalabililty
- New file format
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