Sarquol Ltd

Again, this has come from the internet so I can’t provide its origins. Out of interest, my wife sent it to me:

Married 40 some odd years, I took a look at my wife one day and said, “Honey, years ago, we had a cheap apartment, a cheap car, slept on a sofa bed and watched a 10 inch black and white TV, but I got to sleep every night with a hot 25 Year old blond. Now, we have a nice house, nice car, big bed and plasma screen TV, but I’m sleeping with a 60 year old woman. It seems to me that you are not holding up your side of things. Read the rest of this entry »

It is interesting to speculate on the future once in a while. It isn’t so long ago that Intel was talking about future chips running hotter than the surface of the sun. Now IBM is trying to run chips at near absolute zero:

500GHz frozen chips on the menu at IBM – vnunet.com

It is looking like the data centre of the future is going to be a very inhospitable place. Maybe it will be practical to place them in a satellite and place them in orbit. The cost would be significant, but there are advantages too. In particular there is a lot of solar power available up there. There are a few problems with the plan though – network latency will be a significant issue. Disaster recovery planning will take on a few interesting aspects as well. OK, I’ll admit it this one is probably a few years away from delivery as a practical business plan. If you have some more creative ideas for the location of future data centres e-mail me or add them as comments when this bulletin appears on the web site. Let me know if I can use them in future editions, but also let me know if you want me to keep your name off it.

In the bulletin so far I have mainly concentrated on the subject of Capacity Management as a whole. On engagements with clients, however, it is quite common for me to be called in once there is already an identified performance problem. The good news is that the best approach to resolving a performance problem that already exists is very similar to the Capacity Management already discussed elsewhere. The bad news, however, is that this means going through similar processes in a much reduced timescale. The chances of managing this are greatly improved if the original system project used a capacity management approach on implementation. Read the rest of this entry »

Let us assume that you have started a piece of performance modelling. You have chosen a set of key transactions, or better still have been told what is most important by the business. You may have an idea of the performance levels that the business need (more on this another time), and you start working with the business to work out the volumes that they are expecting to put through the system. To do the appropriate performance modelling you will need to define the behaviour of a “typical user” and then scale this up to produce a total behaviour profile for all users. It is unfortunate that you are unlikely to receive figures that can be used directly from your business users. You have the following choices at this point: a) educate them in the modelling you are doing and the format you need the numbers in, or b) take the numbers they have provided and reproduce them from your modelling. Read the rest of this entry »

Since we are coming into the holiday period I will divert on to a little humour. This is an extract of a list doing the rounds on the internet, and so I can’t provide its source. E-mail me if you want the full list:

1. My mother taught me TO APPRECIATE A JOB WELL DONE.

“If you’re going to kill each other, do it outside. I just finished cleaning.”

Read the rest of this entry »

If you do not already have a performance testing tool and are doing HTTP or HTTPS development then I would recommend that you look at OpenSTA. The tool is open source, and so the only up front cost involved is the time it takes to learn the interface and produce scripts. It isn’t the only open source load testing tool out there, but it has a strong combination of simplicity of use and scripting flexibility. Read the rest of this entry »

A new computer system goes into production and starts with a pilot. A set of load testing is done to make sure that the live user levels can be supported, with some problems. These problems are resolved and maybe some extra hardware purchased to ensure performance at live volumes is acceptable, and then a full roll out is started. The project team are on site for the first few weeks, and resolve the problems that are experienced initially. The system is handed over to support along with a development team member and then the project team is disbanded. The support team are left to complete the roll out process, and the development team member moves on after a while. Read the rest of this entry »

The following story illustrates why capacity management is needed to consider the most appropriate action to improve performance. I suspect you could insert any resource you wish in place of “network” and the assertion would still be valid.

Firms waste billions on network over-design

Who needs desktop Gigabit Ethernet anyway?

http://www.theregister.co.uk/2006/05/22/network_overdesign_gartner/

It is true that simply upgrading hardware until the system performs well can look like an effective solution in many cases. It can avoid often complicated analysis and testing work, and in many cases will be effective in the short term. Simply continuing to throw hardware at problems as a strategy, however, doesn’t really work. The issue is that solving a solution in this manner will generally be a short term fix. If the solution continues to be to keep adding more resources then eventually the costs stack up to be unacceptable. In many cases there will also be a point of diminishing returns where even the best hardware on the market will fail to keep up. A more informed decision can be made by characterising a system and estimating the capacity that may be required to meet future requirements.

When implementing a new system it is common to make high level assumptions about how the system will be used, based on the information provided by the business community on how they expect the system to be used. This form of input tends to be fairly high level, such as the number of transactions per day that they expect once the system is fully operational. This is a strong start point for working out the likely level of demand that will be placed on the system, which is a process that involves a set of estimates and inferred values in order to arrive at a likely behaviour profile. These figures are then used as the basis for performance and load testing of the system. Consider the future briefly though, since this is also when a little forethought in the specification and design of the original system can deliver a huge benefit. Read the rest of this entry »