Microsoft Exchange 2016 RAM Sizing Update

We’re currently in the process of planning to migrate our existing Microsoft Exchange servers to new hardware running Exchange 2016. Up until the past few weeks the Microsoft recommendation with regard to RAM sizing was to avoid going above 96GB total memory per server. I won’t go into the whole history of why this came about but it mostly came down to potential performance issues (for example .Net garbage collection) and a couple other reasons.

Microsoft announced at Ignite 2017 that the maximum memory size will now be increased to 192GB – this is quite welcome as these days in an enterprise setup it is rather difficult to purchase servers with only 96GB while effectively utilising memory channels over a dual socket system. This shows how important it is to keep track of events, we only recently opened a premier support case with Microsoft requesting confirmation that the 96GB limit was still recommended and the answer was ‘yes’. I would like to point out that the CPU core count has not increased from 24 (remember they recommend disabling Hyperthreading) however Microsoft do say they are actively testing systems with ‘dramatically’ higher core counts so keep an eye out for any changes.

If you would like to see the blog posts for yourself the links are provided below –

https://blogs.technet.microsoft.com/exchange/2017/09/26/ask-the-perf-guy-update-to-scalability-guidance-for-exchange-2016/

https://blogs.technet.microsoft.com/exchange/2015/10/15/ask-the-perf-guy-sizing-exchange-2016-deployments/

Interestingly they also announced Exchange 2019 will be coming end of next year with a preview mid 2018 – something to look forward to!

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