This article introduces an update for cluster resiliency improvements in Windows Server 2012. After you install this update, the following issues that you experience are resolved:
Issue 1Consider the following scnario:
- You have the Hyper-V server role installed on a Windows Server 2012-based file server.
- You have lots of virtual machines on a Server Message Block (SMB) share.
- Virtual hard disks are attached to an iSCSI controller.
In this scenario, you cannot access to the iSCSI controller.
Issue 2Consider the following scenario:
- You have a two-node failover cluster that is running Windows Server 2012.
- The cluster is partitioned.
- There is a Cluster Shared Volume (CSV) on a cluster node, and a quorum resource on the other cluster node.
In this scenario, the cluster becomes unavailable.
Note This issue can be temporarily resolved by restarting the cluster.
Issue 3Assume that you set up an SMB connection between two Windows Server 2012-based computers. The hardware on the computers do not support Offloaded Data Transfer (ODX). In this situation, the SMB session is closed unexpectedly.
Issue 4Consider the following scenario:
- You have a Windows Server 2012-based failover cluster.
- You have a virtual machine on a CSV volume on the cluster.
- You try to create a snapshot for the virtual machine. However, the snapshot creation is detected as stuck. Therefore, the snapshot set is aborted.
- During the abortion process of the snapshot, the CSV volume is deleted after the snapshot shares are deleted.
In this scenario, the abortion process is paused automatically because of an error that occurs on the cluster.
Issue 5Assume that you have a Windows Server 2012-based failover cluster. Two specific snapshot state change requests are sent from disk control manager to CSV proxy file system (CSVFS). The requests are present in the same message. In this situation, disk control manager is out-of-sync with CSVFS.
Issue 6Assume that you create a snapshot for a CSV volume on a Windows Server 2012-based failover cluster. When the snapshot creation is still in progress, another snapshot creation is requested on the same CSV volume. In this situation, the snapshot creation fails and all later snapshot creation attempts on the CSV volume fail.
Note You cannot create a snapshot for the CSV volume until the volume fails over or the volume goes offline and then back online.
Additionally, the update also resolves the issues that are described in the following Microsoft Knowledge Base (KB) articles:
2799728 Virtual machine enters a paused state or a CSV volume goes offline when you try to create a backup of the virtual machine on a Windows Server 2012-based failover cluster
2801054 VSS_E_SNAPSHOT_SET_IN_PROGRESS error when you try to back up a virtual machine in Windows Server 2012
2796995 Offloaded Data Transfers fail on a computer that is running Windows 8 or Windows Server 2012
2813630 Virtual machine enters a paused state or a CSV volume goes offline when you try to create a backup of the virtual machine on a Windows Server 2012-based failover cluster
2824600 Virtual machine enters a paused state or goes offline when you try to create a backup of the virtual machine on a CSV volume in Windows Server 2012