8

Chapter 1. The Philosophy of System Administration

Talk of an impending acquisition means that you may end up being responsible for new (and pos 

sibly incompatible) systems in one or more remote locations

Being able to read these signs (and to respond effectively to them) will make life easier for you and

your users.

1.9. Expect the Unexpected

While the phrase "expect the unexpected" is trite, it reflects an underlying truth that all system admin 

istrators must understand:

There will be times when you are caught off guard.

After becoming comfortable with this uncomfortable fact of life, what can a concerned system admin 

istrator do? The answer lies in flexibility; by performing your job in such a way as to give you (and

your users) the most options possible. Take, for example, the issue of disk space. Given that never

having sufficient disk space seems to be as much a physical law as the law of gravity, it is reasonable

to assume that at some point you will be confronted with a desperate need for additional disk space

right now.

What would a system administrator who expects the unexpected do in this case? Perhaps it is possible

to keep a few disk drives sitting on the shelf as spares in case of hardware problems

1

. A spare of this

type could be quickly deployed

2

on a temporary basis to address the short term need for disk space,

giving time to more permanently resolve the issue (by following the standard procedure for procuring

additional disk drives, for example).

By trying to anticipate problems before they occur, you will be in a position to respond more quickly

and effectively than if you let yourself be surprised.

1.10. In Conclusion. . .

While everything discussed in this chapter may seem like a lot of additional work that takes away

from the "real" work of administering systems, actually the opposite is true; only by keeping this

philosophy in mind will you give your users the service they deserve, and reach your full potential as

a system administrator.

1.11. Red Hat Linux Specific Information

This section describes information related to the philosophy of system administration that is specific

to Red Hat Linux.

1.11.1. Automation

Automation of frequently performed tasks under Red Hat Linux requires knowledge of several dif 

ferent types of technologies. First are the commands that control the timing of command or script

execution. The

cron

and

at

commands are most commonly used in these roles.

Incorporating an easy to understand yet powerfully flexible time specification system,

cron

can

schedule the execution of commands or scripts for recurring intervals ranging in length from minutes

1. And of course a system administrator that expects the unexpected would naturally use RAID (or related

technologies) to lessen the impact of a disk drive that fails during production.

2. Again, system administrators that think ahead will configure their systems to make it as easy as possible to

quickly add a new disk drive to the system.