What is the requirement to configure I/O fencing on Virtual Machines.
|Article:TECH148204|||||Created: 2011-01-14|||||Updated: 2011-08-15|||||Article URL http://www.symantec.com/docs/TECH148204|
Virtual Machines were added to an existing cluster with physical nodes. When vxfen was started it failed.
vxfen log showed following errors.
Tue Jan 11 20:30:32 GMT+8 2011 output was VXFEN vxfenconfig ERROR V-11-2-1006 List of coordinator disks in running
cluster is different than local node.
Unable to configure vxfen
Log Buffer: 0xffffffff889b5f40
VXFEN vxfenconfig NOTICE Driver will use SCSI-3 compliant disks.
Tue Jan 11 20:30:32 GMT+8 2011 exiting with 1
Virtual machine and IO fencing should be configured in a particular way.
IO fencing and Virtual Machines should be configured as below;
SCSI-3 Persistent reservations are only supported with raw device mapping (RDM) in physical mode. I/O fencing is not supported with RDM logical mode or with VMDK-based virtual disks. I/O fencing utilizes HBA World Wide Numbers (WWNs) to create registrations on the storage; this has implications in a virtual environment where the HBA is shared between virtual servers on the same physical ESX host as the WWN used for I/O fencing ends up being the same for each virtual machine. CFS virtual machines (in the same CFS cluster) cannot share physical servers as the I/O fencing behavior will result in all nodes from that physical ESX host being fenced out if an event triggers the fencing functionality. In short, if I/O fencing is configured, the CFS nodes (in the same CFS cluster) has to be running on separate physical ESX hosts. NPIV is currently under evaluation for I/O fencing testing when using multiple Virtual Machines on the same physical ESX host.
Article URL http://www.symantec.com/docs/TECH148204