OnLinux

Linux has many tools available for troubleshooting some are easy to use, some are more advanced.

I/O Wait is an issue that requires use of some of the more advanced tools as well as an advanced usage of some of the basic tools. The reason I/O Wait is difficult to troubleshoot is due to the fact that by default there are plenty of tools to tell you that your system is I/O bound, .... read more

http://bencane.com/2012/08/troubleshooting-high-io-wait-in-linux/

Tools to monitor the performance of your Linux OS

1 - top --> CPU usage, memory usage, swap memory, Cache, Buffer Size, PID process user commands.
2 - vmstat -> Virtual Memory Statistics
3 - lsof -> open files list
4 - tcpdump-i eth0 -> Packet Analyzer.
5 - netstat-a -> Network Statistics.
6 - htop -> Process Monitoring.
7 - iotop -> Monitor Linux Disk I / O
8 - iostat -> Statistics in / out.
9 - iptraf.ng -> realtime monotorización lan / ip
10 - Psacct or Acct -> monitor of user activity
11 - Monit -> Linux Processes and tracking services.
12 - NetHogs -> Monitor for process-network bandwidth
13 - iftop - Bandwidth Control Network.
14 - Monitorix - System and Network Monitoring
15 - Arpwatch - Ethernet Activity Monitor - ARP spoofing

create your own linux course outline ..

https://training.linuxfoundation.org/linux-courses/system-administration-training

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Experience with Internet technologies including TCP/IP, HTTP, DNS.

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Have some hands on experience in analyzing logs to identify attack trends.

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