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Chapter 8. Choosing a Platform for the Best Performance

Before you start to optimize your code and server configuration, you need to consider the demands that will be placed on the hardware and the operating system. There is no point in investing a lot of time and money in configuration tuning and code optimizing only to find that your server's performance is poor because you did not choose a suitable platform in the first place.

Because hardware platforms and operating systems are developing rapidly, the following advisory discussion must be in general terms, without mentioning specific vendors' names.

8.1. Choosing the Right Operating System

This section discusses the characteristics and features you should be looking for to support a mod_perl-enabled Apache server. When you know what you want from your OS, you can go out and find it. Visit the web sites of the operating systems that interest you. You can gauge users' opinions by searching the relevant discussions in newsgroup and mailing-list archives. Deja (http://deja.com/) and eGroups (http://egroups.com/) are good examples. However, your best shot is probably to ask other mod_perl users.

8.1.6. The Real Cost of Support

If you are in a big business, you probably do not mind paying another $1,000 for some fancy OS with bundled support. But if your resources are low, you will look for cheaper or free OSes. Free does not mean bad. In fact, it can be quite the opposite—some of the free OSes have the best support available.

This is easy to understand—most people are not rich and will try to use a cheaper or free OS first if it does the work for them. If it fits their needs, they will keep using it and eventually come to know it well enough to be able to provide support for others in trouble. Why would they do this for free? One reason is the spirit of the first days of the Internet, when there was no commercial Internet and people helped each other because someone else had helped them first. We were there, we were touched by that spirit, and we are keen to keep that spirit alive.

Nevertheless, we are living in a material world, and our bosses pay us to keep the systems running. So if you feel that you cannot provide the support yourself and you do not trust the available free resources, you must pay for an OS backed by a company to which you can turn in case of problems. Insufficient support has often been characterized as an important drawback of open source products, and in the past it may have been the main reason for many companies to choose a commercial product.

Luckily, in recent years many companies have realized how good the open source products are and started to provide official support for these products. So your suggestion of using an open source operating system cannot be dismissed solely on the basis of lacking vendor support; most likely you will be able to find commercial support just like with any other commercial OS vendor!

Also remember that the less money you spend on an OS and software, the more you will be able to spend on faster and stronger hardware. Of course, for some companies money is a non-issue, but there are many companies for which it is a major concern.

8.1.7. Discontinued Products

You might find yourself in a position where you have invested a lot of time and money into developing some proprietary software that is bundled with the OS you chose (say, writing a mod_perl handler that takes advantage of some proprietary features of the OS and that will not run on any other OS). Things are under control, the performance is great, and you sing with happiness on your way to work. Then, one day, the company that supplies your beloved OS goes bankrupt (not unlikely nowadays), or they produce a newer, incompatible version and decide not to support the old one (it happens all the time). You are stuck with their early masterpiece, no support, and no source code! What are you going to do? Invest more money into porting the software to another OS?

The OSes in this hazard group tend to be developed by a single company or organization, so free and open source OSes are probably less susceptible to this kind of problem. Their development is usually distributed between many companies and developers, so if a person who developed a really important part of the kernel loses interest in continuing, someone else usually will pick up the work and carry on. Of course, if some better project shows up tomorrow, developers might migrate there and finally drop the development, but in practice people are often given support on older versions and helped to migrate to current versions. Development tends to be more incremental than revolutionary, so upgrades are less traumatic, and there is usually plenty of notice of the forthcoming changes so that you have time to plan for them.

Of course, with the open source OSes you have the source code, too. You can always have a go at maintaining it yourself, but do not underestimate the amount of work involved.



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