Open Sourece Technologies: System administrator

What is a System Administrator ?

A system administrator, systems administrator, or sysadmin, is a person employed to maintain and operate a computer system and/or network. System administrators may be members of an information technology department.
The duties of a system administrator are wide-ranging, and vary widely from one organization to another. Sysadmins are usually charged with installing, supporting, and maintaining servers or other computer systems, and planning for and responding to service outages and other problems. Other duties may include scripting or light programming, project management for systems-related projects, supervising or training computer operators, and being the consultant for computer problems beyond the knowledge of technical support staff. A System Administrator must demonstrate a blend of technical skills and responsibility.

Skills:

The subject matter of systems administration includes computer systems and the ways people use them in an organization. This entails a knowledge of operating systems and applications, as well as hardware and software troubleshooting, but also knowledge of the purposes for which people in the organization use the computers.
However, perhaps the most important skill to a system administrator is problem solving -- frequently under various sorts of constraints and stress. The sysadmin is on call when a computer system goes down or malfunctions, and must be able to quickly and correctly diagnose what is wrong and how best to fix it.
System administrators are not software engineers or developers. It is not usually within their duties to design or write new applications software. However, sysadmins must understand the behavior of software in order to deploy it and to troubleshoot problems, and generally know several programming languages used for scripting or automation of routine tasks.
Particularly when dealing with Internet-facing or business-critical systems, a sysadmin must have a strong grasp of computer security. This includes not merely deploying software patches, but also preventing break-ins and other security problems with preventative measures. In some organizations, computer security administration is a separate role responsible for overall security and the upkeep of firewalls and intrusion detection systems, but all sysadmins are generally responsible for the security of the systems in their keep.

Duties of a system administrator

A system administrator's responsibilities might include:
Analyzing system logs and identifying potential issues with computer systems.
Introducing and integrating new technologies into existing data center environments.
Performing routine audits of systems and software.
Performing backups.
Applying operating system updates, patches, and configuration changes.
Installing and configuring new hardware and software.
Adding, removing, or updating user account information, resetting passwords, etc.
Answering technical queries.
Responsibility for security.
Responsibility for documenting the configuration of the system.
Troubleshooting any reported problems.
System performance tuning.
Insuring that the network infrastructure is up and running.
In larger organizations, some tasks listed above may be divided among different system administrators or members of different organizational groups. For example, a dedicated individual(s) may apply all system upgrades, a Quality Assurance (QA) team may perform testing and validation, and one or more technical writers may be responsible for all technical documentation written for a company.
In smaller organizations, the system administrator can also perform any number of duties elsewhere associated with other fields:
Technical support
Database administrator (DBA)
Network administrator/analyst/specialist
Application analyst
Security administrator
Programmer
System administrators, in larger organizations, tend not to be system architects, system engineers, or system designers. However, like many roles in this field, demarcations between systems administration and other technical roles often are not well defined in smaller organizations. Even in larger organizations, senior systems administrators often have skills in these other areas as a result of their working experience.
In smaller organizations, IT/computing specialties are less often discerned in detail, and the term system administrator is used in a rather generic way — they are the people who know how the computer systems work and can respond when something fails.

Books:
Essential Systems Administration (O'Reilly), 3rd Edition, 2001, by Æleen Frisch
Principles of Network and System Administration (J. Wiley & Sons), 2000,2003(2ed), by Mark Burgess
The Practice of System and Network Administration (Addison-Wesley), 2001, by Thomas A. Limoncelli and Christine Hogan
The Practice of System and Network Administration (Addison-Wesley), 2nd Edition (July 5, 2007), by Thomas A. Limoncelli, Christine Hogan and Strata R. Chalup
Time Management for System Administrators (O'Reilly), 2005, by Thomas A. Limoncelli
UNIX System Administration Handbook (Prentice Hall PTR), 3rd Edition, 2000, by Evi Nemeth, Garth Snyder, Scott Seebass, Trent R. Hein