Symantec Veritas Storage Foundation HP-UX, Installation Manual

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Storage Foundation Cluster File System problems
High availability issues
Network partition/jeopardy
Network partition (or split brain ) is a condition where a network failure can be
misinterpreted as a failure of one or more nodes in a cluster. If one system in the
cluster incorrectly assumes that another system failed, it may restart
applications already running on the other system, thereby corrupting data. CFS
tries to prevent this by having redundant heartbeat links.
At least one link must be active to maintain the integrity of the cluster. If all the
links go down, after the last network link is broken, the node can no longer
communicate with other nodes in the cluster. Thus the cluster is in one of two
possible states. Either the last network link is broken (called a network partition
condition), or the last network link is okay, but the node crashed, in which case it
is not a network partition problem. It is not possible to identify whether it is the
first or second state, so a kernel message is issued to indicate that a network
partition may exist and there is a possibility of data corruption.
Jeopardy is a condition where a node in the cluster has a problem connecting to
other nodes. In this situation, the link or disk heartbeat may be down, so a
jeopardy warning may be displayed. Specifically, this message appears when a
node has only one remaining link to the cluster and that link is a network link.
This is considered a critical event because the node may lose its only remaining
connection to the network.
Caution: Do not remove the communication links while shared storage is still
connected.