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
detects Node A is
registered with the
coordinator disks.
The driver does not
see Node A listed as
member of the
cluster. The I/O
fencing device driver
prints message on
console:
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 is crashed.Node A crashes while
Node B is down. Node
B comes up and Node
A is still down.
Power on the failed
disk array so that
subsequent network
partition does not
cause cluster
shutdown, or replace
coordinator disks.
See “Replacing I/O
fencing coordinator
disks when the
cluster is online”
on page 123.
Node B continues to
operate as long as no
nodes leave the
cluster.
Node A continues to
operate as long as no
nodes leave the
cluster.
The disk array
containing two of the
three coordinator
disks is powered off.
No node leaves the
cluster membership
Overview of Veritas Storage Foundation for Oracle RAC
About preventing data corruption with I/O fencing
52