Hi community!
Here’s a case that BSOD occurs when UltraPath is being installed on a Windows host running the DiskSafe software.
[Symptom]
A Windows host runs DiskSafe, a piece of volume management software from FalconStor. The host is connected to a Huawei storage system, and LUNs are mapped to the host. In this scenario, when UltraPath V100R006 or V100R008 is being installed on the host, Blue Screen of Death (BSOD) occurs. After the host is restarted, BSOD recurs. If LUN mappings are removed, the host can be started normally.
[Fault Diagnosis]
On all disks, DiskSafe loads a filter driver above the UltraPath driver nxup. When UltraPath is transmitting I/Os that are delivered from the upper-layer disk driver to disks, BSOD occurs in the phase where I/Os arrives at the fsefd driver. The cause of BSOD is that the IRQL level is incorrect or invalid memory is accessed.
Figure1 Cause of BSOD
Almost all I/Os result in BSOD. The current dump analysis results indicate that system test I/Os result in BSOD.
Figure1 BSOD caused by system test I/Os
The preceding figure indicates that a TUR I/O passes nxup_ext_a and reaches fsefd, and at this time, BSOD occurs. This problem inevitably occurs. If DiskSafe is not installed, UltraPath works properly. Therefore, it can be concluded that UltraPath and DiskSafe are not compatible with each other.
[Solution]
UltraPath and DiskSafe cannot coexist due to the compatibility problem. Therefore, you can uninstall DiskSafe before installing UltraPath. Alternatively, use the multipathing software provided by the operating system to manage Huawei storage
