On a Storage Fondation 5.1 Service Pack 1 (SP1) for Windows or on a Dynamic Multi-Pathing 5.1 for Windows, Disabling some, but not all, of the paths of a multi-path disk may cause disk loss. This issue has been seen only for HP MSA P2000 array and with Microsoft Clustering.
To workaround this issue and have the disk reappear, perform either:
1. Rescan in the VEA console by right clicking on Storage agent and selecting rescan.
2. At the command line, run "vxassist rescan" to have the disks reappear.