Infrastructure Monitoring

Hi,
I am relatively new to Unix. Today I have attended an interview and they asked me below questions
(a)How do you monitor Unix system?
(b)How do you know every thing is working fine?
(c)How do you know if there are any bottle necks?
(d)How do you know if any process is hanging and draining the resources?
(e)If the application is driven by exchange feeds, how do you know if the feeds are all set up correctly?
(f)Are you aware of any performance monitoring tools?

This is with respect to their application which is a trade processing application.

Please help me improve my knowledge.

Regards

With monitoring tools, or adequate unix commands: top, sar, iostat, vmstat etc...
? By looking at the logs?
by monitoring the system...
top ?
I let others continue and complete!
...


---------- Post updated at 16:30 ---------- Previous update was at 16:27 ----------

About performance monitoring tools, plenty exist from free to $$$$$ all depends on what you are looking for and how much $$$/time you can spare

find out what is Nagios. also see this

try zabbix

To all gurus,
Thanks a lot. This is invaluable.

Regards,
krdblc

iostat, vmstat and netstat are used for performance monitoring