Bugcheck 0xF4 occurs on a Hyper-V guest VM running in Windows Server 2008 R2 while under stress when MPIO PathVerify is enabled

  With the following configuration, guest VM systems may experience Stop 0xF4 errors:

�       Windows Server 2008 R2 x64 with Hyper-V Role installed

�       iSCSI and Multi-Path I/O (MPIO) running

�       Guest VM boot storage (VHD files) on iSCSI storage

�       MPIO path verification is enabled

The stop errors in the guest systems are more likely to occur after a short network interruption, such as a failover of an iSCSI target controller, while under heavy load.

In this scenario, this Windows Server 2008 R2-based computer may unexpectedly crash in the Csrss.exe process. Additionally, you may receive the following Stop error:

STOP 0x000000F4 (0x00000003, parameter 2, parameter 3, parameter 4)
CRITICAL_OBJECT_TERMINATION

There are two conditions that can work together to result in extended iSCSI outages, which may result in the guest system failures.

1. Both the Windows iSCSI and MPIO drivers extensively use worker queue threads to queue work items for processing on iSCSI initiator systems.

Under heavy stress, the delay in worker thread processing may be long enough to result in disk timer expiration on the guest systems. This will cause the removal of the boot drive from the guest system that result in the bugcheck.

2. When PathVerify in MPIO is enabled, it can greatly increase the network and worker queue thread contention, especially if the path verify interval (PathVerificationPeriod) is short.