Personal Documentation UNIX Administration Starters

3.3.2.3 The Solaris sysdef Command Another Solaris command that can be used for this purpose is sysdef. The sysdef command outputs the current system definition in tabular form. It lists all hardware devices, as well as pseudo devices, system devices, loadable modules, and the values of selected kernel tunable parameters. It generates the output by analyzing the named bootable operating system file namelist and extracting the configuration information from it. The default system namelist is devkmem. However, the command output is not entirely comprehensive for figuring out basic hardware information; it is more suitable for kernel−related information. This command should probably not be the first choice.

3.4 Personal Documentation

UNIX administration is a challenging job; it requires a substantial level of expertise and skills. But UNIX administration is also a routine job, in which the tasks can only be successfully accomplished by following the required procedures. To install UNIX, you must follow the vendors instructions and recommendations; to configure an application you must strictly obey configuration rules. There is no room for improvisation; improper settings are the main causes of system instability and all related problems. Bugs in the software are a good excuse for our wrongdoings, but only rarely are they the real cause of the problems we experience. Properly configuring a system, and ensuring all of its settings are correct, is not an easy task. Often there are plenty of small but important details that we must take care of. It is easy to forget these small issues, especially if we only deal with them occasionally. Taking notes on everything done to the system can be very instrumental for future work; such notes can be the lifesaver in some critical situations. These moments are always very stressful, and an administrator has to act quickly and accurately. There is no better advice for that time than to follow your own, already tested and proven notes. Many administrative tasks repeat a number of times; it is common to install the same UNIX version on different machines, to configure hosts in the same network environment, to set the same application software multiple times, etc. Any notes about jobs you have done previously can be very helpful; the length of time between jobs can be large enough that you may forget many important details. Note by note a substantial personal documentation will be built; this is your knowledge database, and it is very important for efficient work. You will always be more familiar with your own documents than with any vendor−provided documentation. There is no need to worry about style, syntax, or language — as long as they are explicit and complete, you will always understand your own texts. A key issue for successful UNIX administration is to be well organized. System administration is based on rules designed by others: different configuration files have different formats and syntax. Each required letter, number, dot, dash, or whatever is specified must be fully respected — there is not a great deal of freedom of choice. A UNIX administrator cannot invent another set of configuration rules, even if the existing ones do not seem very logical or convenient. It simply will not work. Past experiences can save time and make everything easier; copying a workable procedure is definitely more efficient than reinvestigating something you have already done. 78 A very efficient approach to making all system documentation available yet well organized is to put individual personal documents on the company network, creating substantial internal company site−specific documentation, and make the documentation available to all relevant associates. By posting these documents on an internal company Web site if necessary even creating an internal Web site for this purpose, everyone will be able to obtain the necessary information about any described topic. The documentation remains open for any required update or upgrade. To prevent potential frauds, the access to documents should be restricted to administrative personnel only. There are third−party products that provide tools to create internal knowledge databases; in most cases they offer other features, as well. However, they can be costly and sometimes too complex to work with. Creating your own internal, Web−based documentation site is simple, inexpensive, and very efficient.

3.5 Shell Script Programming