Google Networking Best Practices for Large Deployments - Manual (Page 17)

Network Evaluation 17
Collect the following data for each environment, while using Google Apps services available in
your domain. For instance, open Gmail, Google Talk, Google Docs, and Google Calendar.
• Average connections/sec
• Peak connections/sec
• Non-peak connections/sec
Additionally, Google Apps, like many web-based applications that run in the cloud, keeps
several connections open to the remote server to poll for new data. To evaluate the load
caused by these open connections, measure the following in your test environment.
• Minimum amount of connections an idle user has with your browser platform
• Maximum amount of connections an idle user has with your browser platform
Once you have gathered these numbers, you can compile this information to estimate the load
you might experience given your unique environment.
Estimate Expected Proxy Resources Needed
To estimate the amount of load you can expect during a Google Apps rollout, multiply the
number of connections for each test environment by the number of users you expect for that
environment.
Use the following calculations.
Estimated average load = Sum (average load of each test machine environment X
estimated number of users who will use that environment)
Estimated peak load = Sum (peak load of each test machine environment X
estimated number of users who will use that environment)
Estimated idle load = Sum (idle load of each test machine environment X
estimated number of users who will use that environment)
If the estimated average load, plus any additional traffic your proxies handle, exceeds your
current capacity, make plans to expand your proxy server capacity, or change your proxy
server implementation so that your proxy servers do not handle the requests that your users
will make to Google Apps.
Example
In the following example, a large enterprise plans to deploy the following:
• 5000 users running Chrome on Windows 7.
• 3000 users running Firefox on Windows 7.
During benchmarking, tests show the following sample numbers of concurrent connections
through the proxy server. (Note: These are for example only. Your environment will vary.)