Veritas Storage Foundation 5.1 SP1 for Oracle RAC Administrator"s Guide (5900-1512, April 2011)

Table 1-2
I/O fencing scenarios (continued)
Operator actionNode B: What
happens?
Node A: What
happens?
Event
Resolve preexisting
split-brain condition.
See “System panics
to prevent potential
data corruption”
on page 202.
Node B restarts and
I/O fencing driver
(vxfen) detects Node
A is registered with
coordinator disks.
The driver does not
see Node A listed as
member of cluster
because private
networks are down.
This causes the I/O
fencing device driver
to prevent Node B
from joining the
cluster. Node B
console displays:
Potentially a
preexisting
split brain.
Dropping out
of the cluster.
Refer to the
user
documentation
for steps
required
to clear
preexisting
split brain.
Node A restarts and
I/O fencing driver
(vxfen) detects Node
B is registered with
coordinator disks.
The driver does not
see Node B listed as
member of cluster
because private
networks are down.
This causes the I/O
fencing device driver
to prevent Node A
from joining the
cluster. Node A
console displays:
Potentially a
preexisting
split brain.
Dropping out
of the cluster.
Refer to the
user
documentation
for steps
required
to clear
preexisting
split brain.
Nodes A and B and
private networks lose
power. Coordinator
and data disks retain
power.
Power returns to
nodes and they
restart, but private
networks still have
no power.
51Overview of Veritas Storage Foundation for Oracle RAC
About preventing data corruption with I/O fencing