Description:
Memory required per EMS instance.
Symptoms:
Currently, running one instance of  EMS server (32-bit) on a virtual server. Have noticed that adding a second EMS instance of the same server increases memory consumption by roughly 100 MB.  Need to scale up to seven (7) instances and want to know what is the overall memory requirement. The first thought was to multiply the number of extra instances by 100 MB, but need to know if there are more precise guidelines.


Cause:
N/A

Memory required per EMS instance.

There is no direct formula for the memory consumption for an EMS instance. There are many factors that can cause the EMS server process memory footprint to grow, such as:
 
-- Number of the pending messages.
-- Buffers for each connected connections.
-- Number of durables.
-- Number of connection objects, session objects, producers, consumers and temporary destinations.
-- How badly the DB files are fragmented.
-- How many pending messages are in the CM ledger file and whether you export EMS messages to RV CM messages.
-- The size of reserved memory.
-- Number of routes.

You need to perform a test in your environment to estimate the values depending upon your inbound and outbount message rate and traffic on the EMS servers.