What I mean is -- how do you know that you have a performance problem with your network and that moving to GigE will solve it?

oh! Assmuning that if your system machine include 2 DBs, they have been being served about 1000 connections per days. And if you configure DBs cool, monitor it and really tuning it well. What's the problem if your customers claim day by day? You may check, you may generate, and you do everything with your DBs. The performance can not imrpoves more than thing you want.

And, this is important reason: I can not decide what do I do!

Any way, thank you very much!


P/S: I want to monitor processeses, including background processes, so that, I want to view what is the process that hold much memory. Would you like to guide me?

Here is my advice: don't do anything (yet) !
System administrators, even skilled ones, shouldn't do gratuitous tuning on a production platform.
Build a test system similar to your production platform, simulate access to it with increasing load, record usage metrics (CPU, memory, network, disk, ...), identify bottlenecks if any.
Only after completing these steps can you possibly start tuning your machine.
Start with prstat.

Thank all! You are all best!