TroubleShooting policies(排错策略)

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TroubleShooting policies
---edit by Eric Cheung

TroubleShooting:
* Try the easy things %first%
* Check log files %before% configuration files
* Many services have a debugging switch
* Use syntax checkers when available
* Bugzilla: http://bugzilla.redhat.com
* Source RPMs packages may provides insights

TroubleShooting for each type：

1) Things to Check: X
* Never debug X while in runlevel 5!
* Try Xconfigurator (command: redhat-config-xfree86 (2.4 older
kernel), or system-config-display (2.6 kernel) ) first
* X -probeonly (command)
* Is /home or /tmp full? or has a hard quota reached?
* Is xfs (service) running? (service xfs status)
* <Ctrl><Shift> in GNOME

2) Things to Check: Services
* Check the service's log file
BIND,DHCP,NFS,many others: /var/log/messages
Sendmail,IMAP,POP,procmail: /var/log/maillog
Apache: /var/log/httpd/{error,access}_log, plus virtual hosts'
logs
Samba: /var/log/samba/log.{smbd,nmbd}, /var/log/samba/<IP>.log
* Check for successful hostname and IP address resolution
* Check for problems with supporting services and networking
* Check security settings and access permissions
* PAM

3) Things to Check: Networking
* Hostname resolution (/etc/resolv.conf, nslookup, dig...)
* IP configuration (ifconfig, netstat -rn, mtr, traceroute, ping...)
* Default gateway
* Routing problems
* Module specification
* Device activation

4) Things to Check: Booting
* Bootloader configuration (LILO, GRUB)
* Kernel
* /sbin/init, /etc/inittab
* /etc/rc.d/rc.sysinit, /etc/fstab
* /etc/rc.d/rc, /etc/rc?.d/
* /etc/rc.d/rc.local
* X