KB2898774 – Data Loss Occurs On SCSI Disk That Turns Off In WS2012-Based Failover Cluster

Microsoft has released a KB article to avoid data loss occurring when a SCSI disk turns off in a Windows Server 2012-based failover cluster.

Symptoms

Consider the following scenario:

• You deploy a Windows Server 2012-based failover cluster. The cluster contains two nodes (node A and node B).
• A SCSI disk is used for the failover cluster. The disk is a shared disk and is accessible by both node A and node B.
• Node A restarts or crashes. Then, the cluster fails over to node B.
• Node A comes back online.
• Node B is shut down and the cluster fails over to node A.
• You write some data to the disk.
• The disk turns off unexpectedly. For example, the device losses power.

In this scenario, the data that you write to the disk is lost.
Notes

• This issue also occurs when the cluster contains more than two nodes.
• This issue does not occur if the SCSI disk supports the SCSI Primary Commands – 4 (SPC-4) standard.

To resolve this issue, install update rollup 2903938.  It’s an update rollup, so update rollup rules apply – either test like nuts in a lab or wait a month before you approve/deploy it.