Linux Software RAID and Apache Web Server Management

Software RAID Configuration

• Use fdisk or similar tools to create partitions with type 0xfd (Linux RAID). Remember to run partprobe.
• Create and define RAID devices using mdadm: mdadm -C /dev/md0 --chunk=64 --level=5 --raid-devices=3 /dev/sd[b,c,d]1
• Format each RAID device with a filesystem: mkfs.ext3 -j /dev/md0
• Test RAID devices:
  • mdadm --detail /dev/md0
  • mdmonitor provides the notification service.

Software RAID Testing and Reclaiming

• Simulating disk failure: mdadm /dev/md0 -f /dev/sda1
• Recovering from failure:
  • Replace the failed disk.
  • Rebuild the partitions on the new disk.
  • mdadm /dev/md0 -a /dev/sda1
• Monitor /proc/mdstat and syslog for error messages.
• Managing arrays:
  • Disassemble: mdadm -S /dev/md0
  • Assemble: mdadm -A -s

Apache Web Server Management

In RHEL5, the web service is called httpd.

• Start service: service httpd start
• Enable on boot: chkconfig httpd on

Apache Installation

Install via yum:

[root@station ~]# yum install httpd

Check availability: elinks -dump http://localhost

Apache Configuration

The configuration directory is located at /etc/httpd/conf.

• Main configuration file: /etc/httpd/conf/httpd.conf
• Uses XML-like syntax; lines starting with # are comments.

Key Configuration Directives

• DocumentRoot: Root directory for server documents (e.g., DocumentRoot "/var/www/html").
• ServerRoot: Root for configuration files, errors, and logs (e.g., ServerRoot "/etc/httpd").
• Listen: IP address and port to listen on (e.g., Listen 80).
• TimeOut: Seconds the server waits for a non-responsive client (e.g., Timeout 120).
• KeepAlive: Enable or disable persistent connections (e.g., KeepAlive Off).
• MaxKeepAliveRequests: Maximum number of persistent connections (e.g., MaxKeepAliveRequests 100).