Last week a colleague contacted me to get my thoughts on a issue he was facing at a customer with a small VMware vSphere 5.5 environment.
Apparently the customer had faced a power outage for a longer period then their UPS could cope with, the result was 2 hosts and a HP P2000 iSCSI SAN were powered off without a clean shutdown.
When the power was restored this resulted in 1 RAID set being in degraded mode and the other RAID set being OK, while the RAID set was recovering just fine there were some issues on the vSphere environment.
After the hosts booted and vCenter was started, it was possible to connect with the webclient to vCenter. There it looked like the first datastore was OK and the second was not OK, all VM's on the first datastore booted without any issues. But because the second datastore presented itself as a VMFS volume on a snapshot LUN, the VM's that resided on this datastore couldn't be powered on. The real second datastore was not visible at all from vCenter.
I came up short on ideas during the phone call, so my colleague resorted to VMware support (GSS) and they came up with a rather quick solution to this issue. I thought I would share this.
The first thing that was done, was to rename the snapshot datastore. Next they added storage and selected the existing LUN with the re-signature option. After this completed, the only thing left was to re-register the VM's to vCenter that resided on the second datastore.
For me the solution that GSS came up with was a good one, it solved the issue quickly without too much efford.