Is there an upper limit to the number of Secondary sites that can be attached to a single Primary site?

Contributed By: Wally Mead [MS]
No, there is not. We have some customers with over 1,000 Secondary sites per Primary. That's not usually recommended due to administration and other issues, but there is no hard limit, other than the number of 3 character site code permutations.

Generally the replication traffic for a single site that has to replicate administration information down to large numbers of child sites. Advertisements, package definitions, possibly package source files, and Collections all are replicated from parent to child sites. The more child sites you have, the more replication traffic you will have.

Plus, in the scenario of Secondary sites, they don't do much data analysis on their own. As a general rule, and data collected at the Secondary site is packaged up, and sent up to the parent. Some data is then replicated back down to the Secondary site, such as collection members. The more child Secondary sites you have, the more processing is required of the Primary site server.

There isn't really a recommendation on a maximum number of sites. You might hear a "50 child sites per parent", but that was just a guideline that someone in the SMS group came up with in the SMS 1.0 time frame. Hardware is so much more advanced in today's environment, that's not an issue.

We have a number of customers with a couple of hundred Secondaries off a Primary, and all seems to be functioning well for them.