Thanks for the responses. I think I've got it.
Here are my assumptions:
- qmail running as a relay
- peak concurrency of 200
- average msg size of 15K
- a 15K msg requires an average of 20 sec smtp transfer time
15,000 bytes * 200 msgs
----------------------- = 150,000 bytes/sec * 7 bits/byte = 1.0Mb/s
peak bandwidth usage.
20 secs transfer time
So, when qmail hits a peak (perhaps somewhat sustained - remember its a
relay, no spam would hit it) concurrency of 200, and the average msg
size is 15K, we are looking at coresponding peak bandwidth usage of
1.0Mb/s. Sound reasonable?
Regards, Eric Dahnke
PS: from previous posts, I'm assuming that the 1.6 fudge factor (bytes
transfered more than bytes the msg contains) washes with compression at
the router.
