On 14 March 2011 12:08, David kerber <dcker...@verizon.net> wrote: > Dave, could you give us any more information about your network? What is > the piece that's at 80% utilisation when you see the trouble? Is it a > point-to-point connection, or an Ethernet LAN, or what? If it's Ethernet, > what hardware are you using for connection? > > It's our internet connection to the outside world, which is a T-1, with a > Cisco ASA for the firewall. The connections we're processing are from a > bunch of separate customer sites, but which all connect to us through the > customer's gateway.
A T1 used to be 1.5 Mbit/s bidirectional, back when I did my basic network training (which, I admit, is a good few years ago). Is it still? If so, that's quite low. I have 34 Mbit/s down, 1.5 Mbit/s up to my house for the price of a decent restaurant meal for one per month. What might your upgrade options be? Also, see if the ASA can give you any usage statistics. There's a small chance that you're saturating your firewall if you have a very large number of short-lived connections. Cisco's figures don't always stack up here - in the past, I've had to debug load problems with Cisco routers that were supposed to be able to handle two ISDN PRIs, and couldn't when there was heavy call setup and termination load. I accept this isn't quite a parallel case! Tomcat might still be the problem, but I'd certainly take a long hard look at your network infrastructure. Does the server really have to be on your site, or can you have a server in a bunker somewhere that passes hourly / daily reports to your site via a heavily compressed file format? Our telemetry system does that, for example, just running in a VM (for reliability, believe it or not). Cheers, - Peter
