IOPS data for storage devices (wikipedia)

Source: http://en.wikipedia.org/wiki/IOPS

Examples

Core/RAM distribution over several servers (virtual or otherwise) is not described here.

However, for up to 16/24 cores, we believe that a single-platform installation makes sense.

Above this threshold, and to manage populations of tens of thousands of users or more, the architecture must be distributed.

Also, the messaging part as well as the database (which collaborative use/smartphone places heavy demands on) must be kept separate from the rest.

Bandwidth

Bandwidth requirements cannot be predicted as they largely depend on mail traffic.Please note that the data on bandwidth usage of the BlueMind calendar and smartphones below clearly shows the preponderance of mail traffic.

BlueMind Calendar bandwidth

For a user with the Calendar application open in their web browser, in http and in bytes (measured on the network with Wireshark):

• every 30 seconds: one doSync 1067 / 293 (sends local modifications and retrieves changes)
• every 5 seconds: one ping: 898 / 233, i.e. 5388 / 1398 in 30s (one keepalive)

Client to server: 215 bytes/sec (1,067+5,388)/30

Server to client: 56 bytes/sec (293+1,398)/30

With room for maneuver, for 1,000 Calendars running in web browsers:

• Client to server: 500KB/s
• Server to client: 150KB/s

Contacts bandwidth

For a user with the Contacts application running in their browser, in http and in bytes:

144 bytes/second

Specifically:

• a ping every 5 seconds
• a "bmc" every 30 seconds

By doubling the value measured to ensure a comfortable safety margin, we calculate a bandwidth of 288 bytes per second for a user who has launched the Contacts application.

Smartphone bandwidth

Microsoft provides the following ActiveSync ratios: 1.04KB/s/user

i.e. for 100 smartphones: 104Kbit, or 13KB/s

By taking a sensible safety margin of x2, we calculate:

• 100 smartphones == 26KB/s
• 1,000 smartphones == 260KB/s