Performance Monitoring and Statistics

Question 1

top

Answer 1

Display and manage the top processes

Question 2

htop

Answer 2

Interactive process viewer (top alternative)

Question 3

mpstat 1

Answer 3

Display processor related statistics (main processor…stat…1?)

Question 4

vmstat 1

Answer 4

Display virtual memory statistics (virtual memory statistics 1)

Question 5

iostat 1

Answer 5

Display I/O statistics

Question 6

tail -100 /var/log/messages

Answer 6

Display the last 100 syslog messages (Use /var/log/syslog for Debian based systems)

Question 7

tcpdump -i eth0

Answer 7

Capture and display all packets on interface eth0 (ethernet 0, presumably)

Question 8

tcpdump -i eth0 ‘port 80’

Answer 8

Monitor all traffic on port 80 (HTTP)

Question 9

lsof

Answer 9

List all open files on the system

Question 10

lsof -u user

Answer 10

List files opened by user “user”

Question 11

free -h (or -m/-g)

Answer 11

Display free and used memory (-h for human readable, -m for MB, -g for GB)

Question 12

watch df -h

Answer 12

Execute “df -h”, showing periodic updates
What is “df”?

Question 13

mpstat

Answer 13

Display statistics about CPU usage
This is different from “mpstat 1” how?

Question 14

pidstat

Answer 14

Display statistics about processes running