Diagnosing possible intermittent network failures/slowdowns; tool?
Take a look at mtr. It's traceroute and ping consolidated into one tool and continuously monitors the path between two hosts. You get output like that below. It's available as package mtr-tiny for Ubuntu and mtr for CentOS.
My traceroute [v0.75]
somehost.lan (0.0.0.0) Thu Aug 18 20:52:49 2011
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev
1. somehost.lan 0.0% 56 0.3 0.3 0.2 0.5 0.0
2. 192.168.1.254 0.0% 55 82.8 48.1 2.9 100.6 31.5
3. 94-192-160-1.zone6.bethere.co.uk 76.4% 55 11038 11232 11038 11450 156.1
4. 10.1.3.245 25.9% 55 17.6 17.6 16.8 20.6 0.7
5. ???
6. ???
7. linx1-hex.webfusion.com 96.3% 55 23.6 23.8 23.6 24.1 0.3
8. ???
9. supanames-22.supanames.co.uk 0.0% 55 31.4 31.4 30.5 38.0 1.0
I would do this with a small shell script like this:
#!/bin/bash
while true; do
date >> mylogfile.txt
ping -c 5 sometestnode >> mylogfile.txt
sleep 5
done
Run the script like this so it keeps running after you log out:
nohup scriptname.sh &
Once you have waited a suitable amount of time, you'll just need to kill the process and look through your log file. Of course this could be tweaked any which way you want.