Network administrators are often concerned about the availability of file and print
services. Network users are inclined toward intolerance of the services they depend
on to perform vital task responsibilities.
A sign in a computer room served to remind staff of their responsibilities. It read:
All humans fail, in both great and small ways we fail continually. Machines fail too.
Computers are machines that are managed by humans, the fallout from failure
can be spectacular. Your responsibility is to deal with failure, to anticipate it
and to eliminate it as far as is humanly and economically wise to achieve.
Are your actions part of the problem or part of the solution?
If we are to deal with failure in a planned and productive manner, then first we must
understand the problem. That is the purpose of this chapter.
Parenthetically, in the following discussion there are seeds of information on how to
provision a network infrastructure against failure. Our purpose here is not to provide
a lengthy dissertation on the subject of high availability. Additionally, we have made
a conscious decision to not provide detailed working examples of high availability
solutions; instead we present an overview of the issues in the hope that someone will
rise to the challenge of providing a detailed document that is focused purely on
presentation of the current state of knowledge and practice in high availability as it
applies to the deployment of Samba and other CIFS/SMB technologies.