Incorrect Function When Bringing Disk Online in Disk Manager

I was configuring new storage for a Veeam Proxy server, and was surprised to find that I couldn’t bring the volume online. This was a freshly provisioned Fibre Channel LUN on a Nimble AF5000 array. The particular Veeam Proxy in question is a Cisco UCS B200 M3 blade. I created the LUN on the AF5000 and created the initiators. I then configured Fibre Channel zoning on the Nexus switches, went back to Windows and rescanned the storage. The new LUNs appeared in Disk Management, but when attempting to bring them online I received this message:



After some quick troubleshooting, I found that the SAN policy for the Virtual Disk Manager is set to “Offline Shared” by default. The SAN policy controls how SAN LUNs are mounted on a Windows Server. This can be confirmed using DiskPart.

Open a cmd prompt as admin and type in “diskpart”. Then type in “san”. This will show you the current SAN policy.



To resolve this, you need to change the SAN Policy to “Online All”. This can be done with a simple command. Back in the diskpart window, type in “san policy=onlineall” :



Now, go back to disk management (or you can just use diskpart) and bring the volume online, then initialize it.