Administrator Guide

NOTE: When using Replay Manager with Microsoft Hyper-V, only volumes hosting virtual hard disk (VHD or VHDX)

files are included in a snapshot. Virtual machine volumes are not included if the volumes are mapped to a virtual

machine by iSCSI or pass-through.

NOTE: Microsoft Hyper-V Replays create a view volume on the Storage Center for each Replay. All other Replay

Manager extensions do not create a view volume for each Replay. This is a limitation of the Microsoft Hyper-V VSS

writer.

Microsoft does not provide guidelines for the number of virtual machines that can be snapped at a time or the best interval. Most

administrators perform snapshots once a day for most virtual machines, and more frequently on a limited number that require a tighter

recovery point objective. For more information on the specifics of the support policies for Microsoft applications when virtualized, see

these links:

• Microsoft Server Software and Supported Virtualization Environments: support.microsoft.com/kb/957006/

• Support Policies & Recommendations for Exchange in Virtualization Environments: technet.microsoft.com/en-us/library/

cc794548.aspx

Using Replay Manager with Hyper-V on Front-End SAS

• Hyper-V hosts can use either single or multipath I/O on Front-End SAS.

• Hyper-V guests (VMs) can use only single path I/O. Multipath cannot be installed. These VMs must be gen 2. Gen 1 is not supported.

• Dell has opened a ticket with Microsoft to address this situation.

Creating Backup Sets in a Hyper-V Cluster

Virtual machines may be moved among cluster nodes for a variety of reasons. Virtual machines may be moved manually, for example, in

preparation for planned server maintenance. Virtual machines may also be moved dynamically, for example, when the Dynamic

Optimization feature is enabled in Virtual Machine Manager. During Dynamic Optimization, the resources of each node in a cluster are

monitored to optimize the placement of virtual machines initially and during failover.

In an environment where virtual machines move often within a cluster, and where collections of virtual machines do not consistently move

together, each Replay Manager backup set should contain only one virtual machine per CSV. This avoids the need to frequently re-create

backup sets to account for the movement of individual virtual machines.

Support of Recovery with Pass-Through Disks

As Microsoft supports the virtualization of applications like SQL Server and Exchange, more administrators are virtualizing their application

environments and using pass-through disks for data volumes. If there are pass-through disks attached to a virtual machine, Replay

Manager can be installed on the virtual server guest to back up the data volumes for the application. Because of the abstraction layer that

is introduced in virtualizing the hardware, the only way to recover a snapshot directly back to the virtual machine is by using the Microsoft

iSCSI Software Initiator which is available as a free download from Microsoft (for Microsoft Vista and Microsoft Server 2008 (and later),

the iSCSI Software Initiator is included with the operating system). iSCSI uses Ethernet connectivity which is readily accessible by a virtual

machine and is easy to configure both on the server as well as the storage.

VSS Error Event ID 8194

When backing up Hyper-V virtual machines, the following error may be logged in the Windows Event Log:

Event ID 8194

Volume Shadow Copy Service error: Unexpected error querying for the

IVssWriterCallback interface. hr = 0×80070005, Access is denied.

This error does not prevent backup jobs from completing successfully and it can be safely ignored.

Additional Information on Using Replay Manager with

Hyper-V

For further information on how Hyper-V integrates with Replay Manager, see the Dell Storage Center Replay Manager 7 and Microsoft

Hyper-V Best Practices Guide.

See the following link (login required) : http://en.community.dell.com/techcenter/extras/m/white_papers/20437951

Replay Manager Best Practices