06-27-2014 12:54 PM
Hi,
What needs to be done to resolve the issues of,
1) Jeopardy state
2) Split brain
Thanks,
Gary
06-27-2014 01:59 PM
Jeopardy is when you only have 1 remaining heartbeat link remaining:
Split brain is when your cluster partitions so you have 2 (or more) sub-clusters that are not communicating with each other (example in a 2-node cluster you could have a cluster partition of 2 single node clusters - i.e the 2 nodes have lost communcation with each other on ALL heartbeats) - in this sceanrio you risk data corruption as the subclusters make try to write to the data at the same time.
Note there can be a conflict between protecting against Jeopardy and split-brain because to have more than 2 heartbeats means you need more independent hardware which is not often available. For example, the public network is usually configured with 2 NICs (bonding, teaming, port aggregation etc) which requires 2 independent switches and the 2 private heartbeats need to use independent switches also so if you configure a low-pri heartbeat on the public network you should use 4 independent switches and 4 independent NICS, but I often see customers configuring low-pri heartbeats when everything is on 2 or 3 switches or/and less than 2 or 3 dual/quad NICs - this means if you loose 1 dual/quad NIC or switch then you have 2 heartbeats remaining (one private and one low-pri) which are NOT indepentent as loosing another dual/quad NIC or switch will cause both remaining heartbeats to fail at the same time, causing split-brain.
Mike
06-28-2014 02:24 AM
At the time of installation, it asked for creating a virtual LLT link from the NIC.What is use of that?SHall we create it?
Thanks,
Gary