Update is available that improves the resiliency of the cloud service provider in Windows: December 2013

Introduction

This article introduces an update that improves the resiliency of the cloud service provider in Windows 8 and Windows Server 2012. This update is dated December 2013.

This update replaces update 2870270, which is used to improve resiliency. Also, this update includes update 2869923 and update 2908415. Additionally, the update resolves several issues that occur in the following scenario:

• You have a Hyper-V failover cluster.

• The Hyper-V resources are saved in .vhd files on Cluster Shared Volumes File System (CSVFS) volumes.

• You use a backup solution. For example, you use System Center Data Protection Manager (DPM) in the Hyper-V environment.

• You try to perform a backup, and a snapshot is taken of the CSVFS volume.

• The current active node encounters an error, and the cluster fails over to another node.

• DPM may start a consistency check on the volume unexpectedly.

Resolution

This hotfix is also available at Microsoft Update Catalog



A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:

http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

More Information

The update introduces the following configurable new properties:

• The snapshot diff area can be limited from 20 percent of the volume size to a maximum of 1 terabyte (TB). To configure this property, set the SnapshotDiffSize parameter in megabytes (MB).

• The default snapshot lifetime is 7 days. Old snapshots will be deleted automatically by the Cluster service. The minimum value for the snapshot lifetime is 1 day, and the maximum value is 60 days. To configure this property, set the SnapshotAgeLimit parameter in days.

For example, to change the snapshot lifetime on the disk to 5 days, use the following command:Get-clusterresourcetype -name "Physical Disk" | set-clusterparameter -name "SnapshotAgeLimit" -Value 5 A scavenger runs on every cluster node at approximately 3-minute intervals (which is non-configurable). For every CSV resource a given node owns, the scavenger checks the ages of the snapshots owned by that CSV volume, and deletes them if they are older than the SnapshotAgeLimit value.

After the update is installed, the Cluster service logs a Warning event when a snapshot is removed:Important All persistent and non-persistent snapshots on the volume are affected by the configuration. Also, if you set the properties to an arbitrarily high value (for example, you set the SnapshotAgeLimit property to 60 days), failover performance may still be reduced. This can cause a failure in some conditions, depending on the size of the underlying diff areas retained, and depending on the underlying system and storage performance. We recommend that you use the default value for these properties.

Additional file information