Category Archives: Sizing

The little known secret about – Sizing your Exchange RAM


Sizing your Exchange server is a very common task for an Enterprise Architect like me. On a regular basis I will check the recommended Hardware-Sizing for our customers.

Many of our deployments are installed on physical boxes but some are also virtualized. In aspects of sizing there aren’t really any differences. I do not want to share now the well known (you did know this, right)? sizing recommendation from Microsoft: Exchange 2013/2016 Sizing recommendation

I want to share the real numbers. For instance:
A Customer with 2360 Mailboxes is running Exchange 2013 on physical Hardware with 128GB RAM (hey¬† – wasn’t there the recommended limit with 96GB)? on a two node DAG.

Sometimes all databases are on one Server and the RAM Usage is on 101GB. The performance of Exchange is still perfectly – no reports for slow Outlook connections in Online mode or anything else.


Another customer is using a virtualized environment with 64GB RAM for approx. 2200 users. Here we also do not see any issues with the size of RAM

So – just a hundred users less and running fine with 64GB.

Even if there are other recommendations – just check out the downscaling side of live. As long as there are no compliants from your users and Managed Availabilty is running fine (more on this in another post) everything is fine.

The only thing to keep in mind with RAM is: Do not run your Exchange 2013/2016 server with less than 7GB – otherwise you will need a lot of time for wating until tasks are done. Even my demo-environment runs on Windows Azure fine in that configuration (D2 VM)

Your EXGuru – aka Peter Forster – aka Satschent Peter