How much bandwidth does a Domino server need?
We get this question quite often lately obviously driven by who-does-not-need-to-be-named claiming lesser bandwidth requirement. Of course that is utter nonsense. There is no instrinct bandwidth requirement in Domino. After all Notes servers were happily running on 4800 Baud modem connections. Bandwidth is the speed, so when you rephrase the question, you see it is missing half of it: "How fast should [insert-your-favorite-land-transport-vehicle] be?" The logical reply: to do *what*? So when looking for bandwidth requirements you need to know: how much data do I have and in what amount of time do I need (or want) this data to be delivered. So step 1 is to compute these values:
- Average requirements:
[Average/Median number of messages per hour] * [Average/Median size of message] / (360 * [Acceptable average delivery time in seconds])
The 360 is to adjust hour to seconds.
- Peak requirements: [Peak number of messages per hour] * [Peak size of message] / (360 * [Expected maximum delivery time in seconds])
- Corporate habit: we see very often that 80-90% of messages are retrieved in just 2 of 24 hours. so when you calculate 24000 messages/day you mis- calculate your average to be 1000 messages/hour while your true average is 9600 in the relevant hours.
- You underestimate your growth. What might have been enough 3 month ago might not be good enough one year in the future. (IBM internally seems to be a big difference. Using Lotus Quickr and Lotus Connections we actually see a decline in message volume)
- Management (or user) expectation: They would expect prompt delivery event for the biggest messages at peak time (ties a little toward the first point)
- Bandwidth availability. This is mostly an issue on VPN connections. The nominal speed my ISP bills me is far higher that what I ever able to get.