In the early Monday morning, we have found our VMware ESXi 5.0 server showing all VMFS datastores located on direct-attached storage disks (DAS) as offline. The disks themselves were offline as well. The server appeared to function bull all local disks were gone. A graceful shutdown attempt was in vain. After a cold boot one of the VMFS was still offline. The underlying RAID volume was online though.
This server uses Adaptec RAID 51245 controller so we use ARCCONF utility for monitoring and management. A quick glance at the controller’s state and configuration didn’t reveal much: no failed or degraded disks, the number of logical disk is correct.