How to find out and monitor IO spikes history in Linux?

UNIX for Advanced & Expert Users
1

hello all
i have application which according to AWS monitoring is reaching to high spikes of IO at random time .
and causing the server to crash and restart .
my question is how can i find out what cause the spike and if i can't with the native linux tools
what free open source minimon intrusive monitor i can use ?
thanks

2

Greetings,
I would try to write a script for cron using perhaps sar with what you mention my first reflex would be to look at the swap usage side, as most probably, memory issue could be the cause, now we really dont know enough about your server's architecture to be able to give usefull replies...

3

thanks for your reply , the application is java tomcat web server which doing heavy batch operation involve reading and writing to DB which is in different server
can you please explain what is : "swap usage side" how do i measure it and what does it mean ?
also what are the best sar parameters to pinpoint what process operation doing the heavy IO

4

Hi umen...

"swap usage side" means the file and/or partition of a disk or disks used to swap data out of and into memory. Nearly ALWAYS data nowadays but could be overlays of active code in embedded systems.

Surely you have heard of SWAPFILEs used in MS Windows OSes?

Also the /tmp drawer is technically a SWAP area if absolutely necessary...

EDIT:
man swapon for Linux systems...

1 Like
5

thanks
yeah i know what is swap file, i wanted to learn something new from experts

6

For Linux statistics, you can try with

1) sar : If sar was enabled, you can review performance statistics of several days ago, you can use "ksar" to generate the graphs.
2) nmon: is a excellent tools for perfomance analytics, the disadvantage is that you need run the command (manually or with crontab), but you can find multiples tools to generate the graphics.

7

Here is something you obviously haven't known yet: DESCRIBE YOUR PROBLEM concisely first before you expect sensible answers: which OS? which "I/O problem"? Is it network I/O, disk I/O, serial I/O or WTF-I/O?

The way you asked you don't need an expert, you need a magician.