Exchange 2019 memory requirements

Copper Contributor

Hi, I planned to install Exchange 2019 on our infrastructure (400 mailboxes), but memory requirements are 128 GB of RAM!! Is it mandatory or can we install it with less memory (32 GB)? Is someone installed Exchange 2019 on production environment? Maybe is better to install Exchange 2016?

Thank you for your help


3 Replies


For running in a VM it is 'only' a 64GB minimum according to the mailbox role calculator.

Remember that MS were very clear at launch that Exchange 2019 is directed at huge multinationals with tens of thousands of mailboxes or those companies who can't move stuff to the cloud for security reasons. Neither of which will probably worry about the extra cost.


If you don't meet the minimums then I believe MS will still support you but it would be a best-effort rather than we will definitely fix this.


On the other hand the end-of-life dates for 2016 and 2019 are exactly the same so unless there is some super-spiffy thing in Exchange 2019 that you like the look of, unlikely, I know what I would do.




@Blade1966Surely that's a error! It would be crazy if the minimum memory requirement to host mailboxes is 128GB. In Exchange Server 2016 the recommended maximum is 192GB.

@Dan Snape 

No error.

See this -


Mailbox: 128 GB minimum recommended. Exchange 2019 has large memory support (up to 256 GB)


Remember MS are using physical servers to run Exchange online which are presumably coming with at least 128GB RAM. They probably aren't bothering to test anything smaller.