Exchange and Dynamic Memory

Earlier today I talked about SQL Server and Dynamic Memory. What about Exchange? Not surprisingly, the Exchange group do not recommend Dynamic Memory being enabled for virtual machines that are running Exchange. You can get the official text on TechNet under the heading of Dynamic Memory Allocation Considerations. They say: “… for virtual machines that are running Exchange in a production environment, it is best to turn off memory oversubscription or dynamic memory allocation. Instead, configure a static memory size …”.

I’ve heard several times, but not seen any official text, that the Mailbox role does not support Dynamic Memory.  I’m not an Exchange person (I’ve had the “luck” of usually working in sites that use Lotus Domino/Notes) but I believe that Dynamic Memory would cause problems for the Mailbox role.  I have read that it only checks for available memory at start up, grabs what it can, and that’s it.  Adding memory afterwards to deal with memory pressure would be pointless.   Anyway, the Exchange group don’t recommend enabling DM on your Exchange VMs.

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2 Replies to “Exchange and Dynamic Memory”

  1. Aidan,

    I note your mention of experience with Lotus Domino/Notes. Do you have any intention of providing a Lotus Domino and Dynamic Memory article – would certainly be an interesting read. IBM’s system requirements for Domino 8.5.2 still only lists VMware products under its virtualization requirements.

    • Hi Adam,

      My experience of Notes/Domino is purely as a user. I did some searching and these are the platforms I found to be supported:

      – IBM PowerVM Hypervisor on AIX
      – IBM PowerVM Hypervisor on IBM i
      – IBM PR/SM on SLES
      – IBM PR/SM on RHEL
      – IBM z/VM 6.1 on SLES
      – IBM z/VM 6.1 on RHEL
      – VMware ESX and ESXi 4.0 on Windows
      – VMware ESX and ESXi 4.0 on SLES
      – VMware ESX and ESXi 4.0 on RHEL
      – AIX with Workload Partitions (WPARs)

      I found where someone had asked the Hyper-V support question on an IBM forum but it went unanswered. I expected to see VMware support but was surprised to see that 4.1 is not supported.

      Long time readers will know that I am no fan of IBM. I don’t like their 1990’s way of thinking and I don’t like the way the deal with their current/potential customers. And this finding reaffirms that.

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