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Question
Friday, November 9, 2018 7:05 PM
Hi Team,
I am currently deploying Exchange 2016 on 4 Physical servers. Exch physical server has 192 GB RAM and 2 * 28 core CPUs. total logical cores is 56.
Processor(s): 2 Processor(s) Installed.
[01]: Intel64 Family 6 Model 79 Stepping 1 GenuineIntel ~2397 Mhz
[02]: Intel64 Family 6 Model 79 Stepping 1 GenuineIntel ~2397 Mhz
I know this is above the number of recommended CPUs that is recommended but i have no other servers to install Exchange on.
What type of Performance issues am i likely to run into. should i consider take one of the CPUs out. Im sure that will impact how much of the RAM i can use.
All replies (6)
Thursday, November 15, 2018 10:04 AM âś…Answered
Hello
You already know Exchange 2016 is "not supported" above 24 CPU.
This is true that in the real world if you run your Exchange 2016 server it ... works.
I personnally made some tests with 48 processors and 512 GB.
When I say "it works" my answer is true but false.
TRUE because you can see all your Exchange processes/services are working fine.
Sometime you can see some basic errors/warning but cannot explain why these error occurs on your servers.
If you check some key Exchange metrics you see everything *seems* fine.
FALSE because you cannot know how Exchange Server binaries have been developed to benefit (or not) for such a parallelism configuration. Thus you cannot know when and how your Exchange thread will be switched from one core to another. You cannot even know if these binaries have an "hard-coded" processor limit set at 24.
You cannot know what could be the impact on upcoming CU and updates.
In the end you should NOT run Exchange Server on such hardware without modifying it.
Not for a production environment.
Because you cannot guess how your environment will behave.
If Microsoft set a limit to 24 Core, this is because they have a good reason behing that statement.
Let's talk about the "not supported" stuff :
It means that you do not follow Microsoft "Preferred Architecture" in your setup.
You do not even follow the "Best Practices" recommendations from Microsoft.
And you are not in the infamous "custom" level of support.
What does this means?
It means that everytime you will meet some strange behaviours/instability and will request some support from Microsoft you are going to be "on your own" once Microsoft support teams will acknowledge that you do not follow Microsoft recommendations.
Every server providers have some settings in their server Bios to *limit* the number of Core for a socket.
So: open your Bios and leverage the number of Core available to 12 Cores per socket if you have a 2 CPU socket servers.
Florent
Monday, November 12, 2018 5:56 AM
Hi A R PATEL,
A lack of resources may cause services cannot start and a delay on mail flow. You should make sure your resources could meet the minimum requirements for Exchange.
For more information about calculating resources, you can have a look about this article below:
Ask the Perf Guy: Sizing Exchange 2016 Deployments
Regards,
Kyle Xu
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Monday, November 12, 2018 1:07 PM
Kyle,
as mentioned in my original post, the physical servers are OVER SPEC'ed for CPUs. i have read the sizing guide but it doesn't talk about what happens if there are too many cores.
Can anyone else assist?
Thursday, November 15, 2018 9:42 AM
Hi A R PATEL,
Although there is no introduction to Exchange 2016, however from this article, we can know Exchange 2019 only support up to 48 processor core, I think Exchange 2016 may less than it, so 56 processor core may doesn't suitable for Exchange 2016.
Regards,
Kyle Xu
Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact [email protected].
Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.
Thursday, November 15, 2018 12:42 PM
Thanks. Does marking down the cores in the BIOS have the same effect as removing a physical proc?
Friday, November 16, 2018 12:07 PM
Hello
Not exactly.
As you talked about 56 Core I guess you are using two Xeon with 14 Core per socket and hyperthreading is activated (2 sockets x 14 Core x hyperthreading = 56)
If you limit the number of Core to 12 *and* disable Hyperthreading you will get 24 Core (2 x 12).
Your operating system will never know you have lowered the number of Core.
The only thing he will know is the NUMA: 2 sockets with 12 Core (because Windows Server is "NUMA aware").
Best regards
Florent