Learning Red Hat Linux (3rd Edition) [Electronic resources] نسخه متنی

9.2 Administering Red Hat Linux by Using the System Tools Menu

The System Tools menu of the
GNOME and KDE desktops provides access to a set of tools that help
you administer Red Hat Linux. The distinction between these tools and
the tools provided by the System Settings menu is rather arbitrary.
That is, any given tool could as likely have been placed on one menu
rather than the other. Generally, items on the System Tools menu
perform an action, whereas items on the System Settings menu let you
configure a facility. But, exceptions to this rule of thumb abound.

The tools provided by the System Tools menu are:

Disk Management

Provides access to the User Mount Tool, which lets users mount,
unmount, and format filesystems

Floppy Formatter (GNOME only)

Provides access to the Format a Floppy tool, which formats floppies

Hardware Browser

Provides access to the Hardware Browser tool, which displays
information about system hardware

Internet Configuration Wizard

Provides access to a wizard that assists you in creating new network
connections

Kickstart

Provides access to the Kickstart Configurator tool, which lets you
specify the parameters for automated installation of Red Hat Linux

Network Device Control

Provides access to the Network Device Control tool, which lets you
configure and administer network devices and connections

Red Hat Network

Provides access to the Red Hat Update Agent, which assists Red Hat
Network subscribers in updating their systems

System Logs

Provides access to the System Logs tool, which lets you view the
contents of system log files

System Monitor

Provides access to the System Monitor tool, which lets you view
system performance and resource consumption information

Terminal

Provides access to a shell, which lets you enter commands

Traceroute

Provides access to the My Traceroute tool, which lets you determine
the network distance to a specified host

This section describes several of the tools. However, it does not
explain the Floppy Formatter, since that tool appears only on the
GNOME menu and since its functions are also provided by the Disk
Manager. Some of the tools are described elsewhere in this book. For
instance, Chapter 8 explains the Red Hat Update
Agent. The Network Device Control and Traceroute tools concern
network configuration and administration, which are topics considered
in Chapter 10 and
Chapter 11. The Kickstart tool is primarily used by
enterprise system administrators and is not described in this book.
And, I dispense with explanation of the Terminal tool, since its use
should be self-evident.

9.2.1 Managing Disks

The Disk Management tool lets you
mount and unmount
filesystems. It also lets you
format filesystems. To launch the tool, choose System Tools
Disk Management from the GNOME or KDE menu. Figure 9-21 shows the tool.

Figure 9-21. The Disk Management tool

The tool shows a list of configured filesystems, taken from
/etc/fstab. To mount a filesystem, select the
filesystem and click Mount. If you mount a floppy or CD-ROM under
GNOME, an icon representing the mounted filesystem appears on the
desktop. Click the icon to browse the filesystem.

To unmount a mounted filesystem, select the filesystem and click
Unmount. The usual restrictions apply concerning the inability to
unmount a file that is in use.

To format a filesystem, select the unmounted filesystem and click
Format. A dialog box appears, as shown in Figure 9-22. The dialog box lets you choose the type of
filesystem to create. For floppies, you may find it convenient to use
the vfat file system, which can be
read by Linux and Windows 9x, ME, 2000, and XP. For other purposes,
you should generally use the standard Linux filesystem type,
ext3. The dialog box also lets you
choose whether a low-level format should be performed. Generally, you
should perform a low-level format only when formatting a floppy.

Figure 9-22. Formatting a filesystem

9.2.2 Browsing Hardware Devices

The Hardware Browser tool lets you view
information describing the system's hardware
devices. To
launch the tool, select System Tools Hardware
Browser from the GNOME or KDE menu. Figure 9-23
shows the tool. When it starts up, the tool probes your system and
may require a minute or so to complete its work. During that time,
the system may become unresponsive.

Figure 9-23. The Hardware Browser tool

To use the tool, click a device in the list at the left side of the
window. A description of the device appears in the right side of the
window. The tool does not let you change or configure devices. It
merely lets you view information describing them.

9.2.3 Monitoring the System

The System
Monitor tool lets you view information about system and user
processes (running programs). It also lets you view CPU, memory, and
disk space usage data. Essentially, the tool combines the functions
performed under
Windows by the
Task Manager and System Information applets. To launch the tool,
choose System Tools System Monitor from the GNOME
or KDE menu. Figure 9-24 shows the tool.

Figure 9-24. The System Monitor tool

The display uses a tree control that displays members of a process
group under their parent processes. Click the triangle next to the
name of a parent process to expand or collapse the tree. To view
extended information about a process, select the process and click
More Info. The bottom pane of the tool is changed to show information
about the selected process, as shown in Figure 9-25.

Figure 9-25. Extended process information

You can terminate a process by selecting it and clicking End Process.
However, you should do so only judiciously. Terminating a necessary
process or terminating a process at an unsuitable time may
destabilize your system. Generally, you should terminate only
processes that appear to be hung.

If the list of processes is long, you may find it convenient to use
the Search box. Or, you can use the View list to view all processes,
processed owned by your user account, or active processes.

Clicking the System Monitor tab displays information like that shown
in Figure 9-26. The tab includes graphs that provide
a running display of CPU, memory, and swap space usage. In addition,
the tab includes a list box that displays the used and total space
associated with mounted disk partitions.

Figure 9-26. The System Monitor tab

9.2.4 Viewing System Logs

The System
Logs tool lets you view information contained in system log files,
which record information about important events. The tool is
especially helpful in troubleshooting system problems, because log
files may contain relevant entries that indicate or suggest the cause
of the problem.

To launch the tool, choose System Tools System
Logs from the GNOME or KDE menu. Figure 9-27 shows
the tool. To view log entries, select the desired log file in the
left part of the window. The log entries appear in the right part of
the window. To find a particular entry or set of entries within a log
file, type text into the textbox labeled "Filter
for." The tool will then display only log entries
containing the specified text. To disable the filter, click Reset.

Figure 9-27. The System Logs tool

The log files
available for viewing depend on which packages are installed. The
standard log files are:

Boot Log

Contains information about services started and stopped during system
boot up and shutdown

Cron Log

Contains information about the cron service, which runs tasks at
scheduled times

Kernel Startup Log

Contains information recorded during system boot up

Mail Log

Contains information about the mail server and mail messages

News Log

Contains information about the USENET news service

RPM Packages

Contains information about package installations and removals

Security Log

Contains information about logins and certain service start ups and
shutdowns

System Log

Contains general-purpose entries not sent to another log and some
important entries also sent elsewhere

Update Agent Log

Contains entries describing actions performed by the Red Hat Update
Agent

XFree86 Log

Contains entries logged by the X server