Does anyone know any rules of thumb (or better) with regards to hardware requirements for a dedicated distributor server? i.e. Based on estimate metrics (e.g. number of subscribers, publishers, tables, average table size, average update frequency, etc) is there some way to calculate a minimum RAM/CPU requirement for the distributor?
More Info
We'll likely be using SQL Server 2012 for the distributor, though the publishers and subscribers are currently a mix of 2008 and 2008 R2.
The distributor will be clustered to ensure high availability. We'll go for active/active to make optimal use of resources, sending half the publishers to one and half to the other, but will ensure that each node in the cluster's spec satisfies the minimum spec so that should one node go down the solution can still cope.
Background Info
We've been using replication to allow our international BI system to pull data from our transactional systems without impacting performance, with the BI servers hosting the distributor. Going forwards we're hoping to move this distribution onto a separate server, so that we can provide replication as a service to the BI team and to other teams requiring this (i.e. local BI teams from various countries & our in house monitoring system). We expect to see an increase in the number of tables being replicated as well as in the number of subscribers and publishers (as we'll be including our non-production systems also).
Thanks in advance.