Virtualisation and Exchange 2010 DAG

Just a quick note – are you supported if you virtualise Exchange 2010 mailbox servers hosting Database Availability Groups ? The short answer is “yes”. The long answer is “Yes ….. unless you want to use Live Migration / XenMotion / VMotion … then you are NOT supported”.

To explain, DAG is a high availability strategy in and of itself. If you want to virtualise servers hosting DAG then you may but those servers should run on stand alone virtualisation hosts. Layering any sort of hardware higher availability on top of DAG high availability will invalidate your support. In truth, this shouldn’t be an issue as virtualisation only provides redundancy at the hardware level with Live Migration / XenMotion / VMotion whereas Exchange DAG provides hardware, O/S, binary and data redundancy (i.e. full redundancy) but you should take account of this in any plans you have for virtualising Exchange 2010.

2 Responses to “Virtualisation and Exchange 2010 DAG”

  1. Fred Baxter says:

    I am new to Citrix. So I ask, Is there a way to run a Citrix XenServer with HA for other VMS and exclude the exchange VM’s from the Motion part of HA? This would allow me to us Motion for other servers and still leverage virtualization for exchange

  2. Philip Flint says:

    Hi Fred

    HA in XenServer allows machines on a failed host to restart on another host. Disabling this behaviour for individual virtual machines is a simple tick box. To prevent machines from being migrated from one host to another by way of XenMotion you need to place them on non-shared storage. That is, create a storage repository that only one host has access to and place the VM files on there. In that way Exchange can be virtualised and not moved from one host to another leaving you fully supported. The storage repository can be on local disk, iSCSI or a SAN, but should not be shared with other hosts.

    Hope this helps

    Phil

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