Description

Many of us sometimes get confused regarding this Cluster attribute "UseFence". How is it being used, why and when can we use that attribute.

Hopefully, this article clears some of the confusion there.

This cluster attribute only get used whenever you need a local failed-over diskgroup controls by VCS  (not a shared diskgroup) to be imported with SCSi-3 reservation keys.

As part of a DiskGroup agent's function, it checks the existence of this attribute.

If this attribute sets to SCSI3,  the agent will then import the local failed-over diskgroup using SCSI-3 reservation keys.  Remember, this is only for local failed-over diskgroup which is being controlled by VCS.

The shared diskgroup on the other hand uses the configuration sets on /etc/vxfenmode  file. If the attribute 'vxfen_mode' sets to scsi3, as part of starting up the CVMCluster, it will then import the shared diskgroup with the SCSI-3  reservation keys.  It does not look at 'Cluster' attribute 'UseFence' on the main.cf file.

So, to summarize all of the above, in order to make use of fencing functionality (ie: a SCSI-3 keys) :

* For shared diskgroup, it uses 'vxfen_mode' attribute on the /etc/vxfenmode configuration files.