Red Hat Enterprise Linux 5 Administration Unleashed

ContentsxiiiPart V Monitoring and Tuning 40120 Monitoring System Resources 403Reporting Filesystem Usage ............................................................403Determining Filesystem Usage ................................................404Reporting Open Files .............................................................406Reporting Disk Performance ...........................................................407Using iostat .........................................................................407Using sar .............................................................................408Reporting System Processes ............................................................410Reporting on the System Processors .................................................412Reporting Memory Usage...............................................................413Reporting on the Network Subsystem ..............................................415Generating a System Report ...........................................................417Locating Log Files.........................................................................418Viewing Log Files with Logwatch ....................................................419Understanding the Logwatch Configuration..............................419Customizing Logwatch Configuration ......................................419Customizing the Logwatch Scripts ...........................................421Creating Service Filters ..........................................................421Summary ....................................................................................42221 Monitoring and Tuning the Kernel 423Using the /proc Directory ..............................................................423Using sysctl to Change Values.................................................425Optimizing Virtual Memory ...........................................................426Managing Memory with NUMA ......................................................430Using AltSysRq to Execute System Requests ......................................432Saving Kernel Dumps for Analysis ...................................................433Booting with Kexec ...............................................................434Reserving Memory for the Secondary Kernel .............................435Selecting Location for Dump File.............................................436Additional Kdump Options ....................................................438Starting and Stopping the Kdump Service .................................439Activating Kdump with a Graphical Application ........................439Testing Kdump .....................................................................440Analyzing the Crash..............................................................440Setting SMP IRQ Affinity ...............................................................443Enabling NMI Watchdog for Locked Systems.....................................445Profiling with SystemTap .......................................................447Summary ....................................................................................448