Pertaining to your original problem I noticed this article...Virtualizing Microsoft Lync Server – Let's Clear up the Confusion | Virtualize Business Critical Applications - VMware B…
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On the fourth point where the writers have stated that VM portability “breaks the inherent availability functionality in Lync Server pools”, we are unaware of the “breakage” alluded to in the document. The VMware’s “portability” feature is vMotion, a feature that has been in long use for clustered critical applications like Microsoft Exchange Server (DAG) and Microsoft SQL Server (MSCS or AlwaysOn). We are not aware of any documented incidents of “breakage” attributable to vMotion operations on these workloads, or even for Lync.
In the “Host-based failover clustering and migration for Exchange“ section of its Exchange 2013 virtualization whitepaper, Microsoft defined the following strict criteria for its support of VM “portability” for Exchange workloads:
- Does Microsoft support third-party migration technology? Microsoft can’t make support statements for the integration of third party hypervisor products using these technologies with Exchange, because these technologies aren’t part of the Server Virtualization Validation Program (SVVP). The SVVP covers the other aspects of Microsoft support for third-party hypervisors. You need to ensure that your hypervisor vendor supports the combination of their migration and clustering technology with Exchange. If your hypervisor vendor supports their migration technology with Exchange, Microsoft supports Exchange with their migration technology.
- How does Microsoft define host-based failover clustering? Host-based failover clustering refers to any technology that provides the automatic ability to react to host-level failures and start affected virtual machines on alternate servers. Use of this technology is supported given that, in a failure scenario, the virtual machine is coming up from a cold boot on the alternate host. This technology helps to make sure that the virtual machine never comes up from a saved state that’s persisted on disk because it will be stale relative to the rest of the DAG members.
- What does Microsoft mean by migration support? Migration technology refers to any technology that allows a planned move of a virtual machine from one host machine to another host machine. This move could also be an automated move that occurs as part of resource load balancing, but it isn’t related to a failure in the system. Migrations are supported as long as the virtual machines never come up from a saved state that’s persisted on disk. This means that technology that moves a virtual machine by transporting the state and virtual machine memory over the network with no perceived downtime is supported for use with Exchange. A third-party hypervisor vendor must provide support for the migration technology, while Microsoft provides support for Exchange when used in this configuration.
vMotion, DRS and vSphere HA satisfy all of those requirements without exceptions.
Granted, when not properly configured, a vMotion operation can lead to a brief network packet loss which can then interfere with the relationship between/among clustered VMs. This is a known technical condition in Windows clustering which is not unique to vMotion operations. This condition is well understood within the industry and documented by Microsoft in its Tuning Failover Cluster Network Thresholds Whitepaper.
This is further helpfully documented by Microsoft in the following publication: Having a problem with nodes being removed from active Failover Cluster membership?
Backup vendors have also incorporated these considerations into their publications. See: How do I avoid failover between DAG nodes while the VSS snapshot is being used?
Like most other third-party vendors supporting Microsoft’s Windows Operating System and applications, VMware has incorporated several of the recommended tuning and optimization steps contained in this whitepaper into several of our guides and recommendations to our customers. See our Microsoft Exchange 2013 on VMware Best Practices Guide for an example.
The VMware’s Microsoft Exchange 2013 on VMware Best Practices Guide includes several other configuration prescriptions that, when adhered to, minimize the possibility of an unintended failover of clustered Microsoft application VMs, including the Lync Server nodes. We wish to stress that our “portability” features do not negate or impair the native availability features of Microsoft Lync Server workloads.
We are unaware of any technical impediments to combining vSphere’s robust and proven host-level clustering and availability features with Microsoft Lync Server’s application-level availability features and we encourage our customers to continue to confidently leverage these superior combinations when virtualizing their Lync servers on the vSphere platform. In the absence of any documented and proven incompatibility among these features, we are confident that customers virtualizing their Microsoft Lync Server infrastructure on the vSphere platform will continue to enjoy the full benefits of support to which they are contractually entitled without any inhibition.
In the unlikely event that virtualizing Lync Server workloads results in a refusal of support from Microsoft to a customer, such customers can open a support request ticket with VMware's Global Support Service and VMware will leverage the framework of support agreements among members of the TSANet "Multi Vendor Support Community" to provide the necessary support to the customers. Both Microsoft and VMware are members of the TSANet Alliance.
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