Google Networking Best Practices for Large Deployments - Manual (Page 16)

16 Networking Best Practices for Large Deployments
% iperf -s
Note: WAN Bandwidth tests are intrusive and can affect network performance. Run these
tests during off-hours to gather data while causing the minimum possible the impact to
your network. If you need to run these tests during business hours, be careful of
possible effects this test may have on your network performance.
Network Testing Tools
You can obtain the tools discussed above from the following online sources:
• Download the
Hping
packet analyzer tool from hping.org .
• Download the
iperf
bandwidth performance measuring tool from SourceForge .
Proxy Server Evaluation and Sizing
In a cloud computing environment, there are typically more outbound requests for external
hosts than are generated in a legacy environment. The increase in outbound requests may
impact the number of proxy servers required in your network.
If you intend for your users to connect to Google Apps through a proxy server, you can
determine what level of proxy server load to expect by running these tests beforehand. Use
this information to estimate whether you need to increase your proxy server capacity.
Follow these steps to evaluate your proxy server needs:
1. Create a test environment with each platform and browser that you plan to use in your
user environment.
2. For each browser, measure the number of connections that occur during testing, including
minimum and maximum concurrent connections, both for idle use and active use.
3. Based on this information and the number of users you expect on your system, calculate
expected number of connections for your proxy server.
4. Use these calculations to plan for any proxy server capacity changes needed.
See below for more information on these steps.
Benchmark Proxy Load Per User
To benchmark the amount of proxy resources used by a typical user, establish a testing
environment where you can test the various platforms and browsers that you support. Your
testing environment should include testing machines on your network that can connect to
Google Apps using the same routes that you plan to use for your users. (For example, if you
plan to deploy users with Microsoft Windows 7, with Chrome 10 and Firefox 3.6 as your
standard OS and browsers, use this same environment when running benchmark tests.) Once
your testing environment is ready, direct traffic to a test proxy where you can measure the
number of connections.