A device backing some part of the VMFS volume is offline

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

The esx.problem.vmfs.extent.offline message is received when an ESXi host loses connection to a storage device that backs an entire VMFS datastore or any of its extents.

Impact

I/O to virtual disk (VMDK) files that reside on the offline device might slow down or fail. This might cause virtual machines that have VMDKs residing on that device to become unresponsive or even fail.

Example

This loss of connection can happen when a switch or cable that connects the device to the ESXi host is disconnected or when the device is reformatted to be used by another volume.

Resolution

Detect the problem with device connectivity and restore connectivity to the device. If the device has been reformatted and used by another volume, then this part of the original volume is lost forever and cannot be recovered.
 

Additional Information

To determine which devices back a vmfs volume, and if one or more devices may be offline, run:

vmkfstools -Ph /vmfs/volumes/<datastore>