Linux+ Networking Chapter 13

When an application stops functioning, the first step to try is to restart the application. This is because restarting the application can help resolve any temporary glitches or errors that may be causing it to stop functioning. It is a simple and quick solution that can often fix the problem without the need for further troubleshooting or research. Researching the solution using the Internet may be helpful in some cases, but it should be tried after restarting the application. Switching to Single User Mode or killing all other applications running in memory are not relevant solutions for resolving a non-functioning application.

Delegate responsibility is not a common troubleshooting procedure because troubleshooting typically involves identifying and resolving issues independently or with a team. Delegating responsibility would involve assigning the problem-solving task to someone else, which goes against the idea of troubleshooting. The other steps mentioned - testing the solution, isolating the problem, and collecting information - are all common troubleshooting procedures that help identify and resolve issues effectively.

Linux administrators spend the most time on monitoring during the maintenance cycle. Monitoring involves constantly observing the system's performance, identifying any issues or abnormalities, and ensuring that everything is running smoothly. This includes monitoring system logs, network traffic, resource usage, and other critical metrics. By closely monitoring the system, administrators can proactively identify and address any potential problems before they escalate, preventing downtime and ensuring the overall stability and efficiency of the Linux environment.

The ulimit command is used to set or display the resource limits of the current shell and any child processes. By using the ulimit command with appropriate options, the number of filehandles that programs can open in a shell can be increased. This is useful when dealing with applications that require a large number of open files, such as servers or databases.

The file "sa19" is likely to be found in the /var/log/sa directory over time.

When the fsck command cannot repair a nonroot filesystem, it does not necessarily mean that all data should be immediately restored from tape backup. There can be other options to recover the data, such as using data recovery tools or consulting with experts. Therefore, the statement "you should immediately restore all data from tape backup" is not always true.

The correct answer is bad, because the processor is idle 10% of the time and perhaps a faster CPU is required. A high percentage of idle time indicates that the processor is not being fully utilized and could potentially benefit from a faster CPU to improve overall performance.

The command "ldd" is used to indicate the shared libraries required by a certain executable program. It helps to identify the dependencies of the program on shared libraries, allowing users to ensure that all necessary libraries are present and properly configured. This command is commonly used in Linux systems to troubleshoot issues related to missing or incompatible libraries.

The command "patch" can be used to apply a patch to kernel source code.

Kudzu is a program that detects and installs new hardware detected at boot time. It is commonly used in Linux distributions to automatically configure and set up newly detected hardware devices. Kudzu helps to simplify the process of adding new hardware to a system by automatically detecting the hardware and configuring the necessary drivers and settings. This allows users to easily install and use new hardware without the need for manual configuration.

The command "setserial" can be used to modify the IRQ and I/O address settings of a serial device.

The correct answer is /lib/modules/(kernel-version). This directory stores most modules on a Linux system. Modules are small pieces of code that can be added or removed from the running kernel without the need to restart the system. The /lib/modules directory contains subdirectories for different kernel versions, allowing for easy management and organization of modules.

The command "sar -W 3 50" will collect 50 swap statistics every 3 seconds. The "sar" command is used for system activity reporting, and the "-W" option specifically collects swap space statistics. The numbers following the "-W" option indicate the interval (3 seconds) and the count (50) for collecting the statistics.

The command "mkinitrd" can be used to create a ramdisk that will be used at boot time to load SCSI support.

The command "mkbootdisk" can be used to create a system boot disk.

To compile the Linux kernel, you must be in the "/usr/src/linux" directory. This directory contains the source code for the Linux kernel, which is necessary for compiling and building the kernel. Being in this directory allows you to access and modify the necessary files and configurations required for compiling the kernel successfully.

The commands "insmod" and "modprobe" can be used to insert a module into the Linux kernel. "insmod" is used to insert a module directly into the kernel, while "modprobe" is used to automatically load any dependencies and insert the module into the kernel.

The correct answer is that you can recompile the kernel to add support for a certain hardware device, remove support for a certain hardware device, change kernel features, and improve system performance. Recompiling the kernel allows you to modify its configuration and settings, enabling you to add or remove support for specific hardware devices. It also allows you to make changes to the kernel's features and functionalities, as well as optimize its performance for your specific system requirements.

The commands "free", "sar", and "vmstat" can be used to display memory statistics. The "free" command shows the amount of free and used memory in the system. The "sar" command provides system activity reports, including memory usage. The "vmstat" command displays virtual memory statistics, including information about memory usage, paging, and swapping. The "iostat" command, on the other hand, is used to display input/output statistics and is not directly related to memory statistics.

The files /etc/modprobe.conf and /etc/rc.d/rc.local can be used to load modules upon system startup. The /etc/modprobe.conf file is used to configure kernel modules, including loading them at system startup. The /etc/rc.d/rc.local file is a script that is executed during the boot process, and it can be used to run commands or scripts, including loading modules. The other options (/etc/fstab and /etc/modtab) are not used for loading modules at system startup.