We have an weird issue in Windows 2008 Server , where 4 to 5 Drive Letter missing ( out of 28 LUNs) , with inaccessible state. Details are below
Array Details: Clarrion & VNX ( issue is only from Clariion) - three different arrays - two are clarriion and one is VNX
Host:Windows 2008 R2 Sp1
Powerpath : 5.5
But after LUN remapping or server reboot , Drives become normal . However , some times when we unmap and remap, a another new LUN/Drive will experience the same behavior.
Note: All the LUNs are used as a windows share mount point.
Even on disk management , Drive was showing without a mount point letter and fully non-utilized.
I am not sure , what could be the problem from storage side.
This may be due to PowerPath and when it sees the disks. Try saving the PowerPath configuration once all the disks are assigned correctly on the host. See the PowerPath User Manual and look for saving the configuration.
Disk was visible in powerpath level, However, Windows drive letter /configuration was missing and changed into an unreadable state.
The array does not change the Host LUN Number once it's set so the Windows driver letter is assigned when the host boots and it enumerates the bus - the HLU number of the LUN on the array is then matched to the drive letter that's kept in the PowerPath config - if it's not saved, then the order may be off - this is PowerPath and not the array.
There is no HLU change, even at the power path level LUNs are visible without any issues . That's why skeptical , how powerpath could add an impact to this situation.
If the drives are still showing up in PowerPath, but not in Explorer, then to me that would point to Windows. Have you checked on the Clariion arrays to see if there are any Event messages to indicate errors at the array level?