Veritas Storage Foundation 5.1 SP1 Cluster File System Administrator"s Guide (5900-1738, April 2011)

Table 2-1
I/O fencing configuration files (continued)
DescriptionFile
When I/O fencing starts, the vxfen startup script creates this /etc/vxfentab file on each
node. The startup script uses the contents of the /etc/vxfendg and /etc/vxfenmode files.
Any time a system is rebooted, the fencing driver reinitializes the vxfentab file with the
current list of all the coordinator points.
Note: The /etc/vxfentab file is a generated file; do not modify this file.
An example of the /etc/vxfentab file in a disk-based fencing configuration on one node resembles
as follows:
/dev/vx/rdmp/c1t1d0
/dev/vx/rdmp/c2t1d0
/dev/vx/rdmp/c3t1d0
For server-based fencing, the /etc/vxfentab file also includes the security settings
information.
For server-based fencing with single CP server, the /etc/vxfentab file also includes the
single_cp settings information.
/etc/vxfentab
How disk-based I/O fencing works in different event scenarios
Table 2-2 describes how I/O fencing works to prevent data corruption in different
failure event scenarios. For each event, review the corrective operator actions.
Table 2-2
I/O fencing scenarios
Operator actionNode B: What
happens?
Node A: What
happens?
Event
When Node B is
ejected from cluster,
repair the private
networks before
attempting to bring
Node B back.
Node B races for
majority of
coordinator disks.
If Node B loses the
race for the
coordinator disks,
Node B panics and
removes itself from
the cluster.
Node A races for
majority of
coordinator disks.
If Node A wins race
for coordinator disks,
Node A ejects Node B
from the shared disks
and continues.
Both private
networks fail.
39Storage Foundation Cluster File System architecture
About I/O fencing