Split-brain (Computing)
Encyclopedia
Split-brain, named by analogy with the medical Split-brain
syndrome, occurs when two parts of a computer cluster are disconnected, each part believing that the other is no longer running.
High-availability cluster
s usually use a heartbeat private network
connection which is used to monitor the health and status of each node in the cluster. One subtle, but serious condition every clustering software must be able to handle is split-brain.
Split-brain occurs when all of the private links go down simultaneously, but the cluster nodes are still running.
If that happens, each node in the cluster may mistakenly decide that every other node has gone down and attempt to start services that other nodes are still running. Having duplicate instances of services may cause data corruption
on the shared storage.
This problem can lead to data inconsistency. To prevent it computers should use redundant communications and fall down to an auto-fencing
mode when the peers look like they are down. This means they should run in a limited mode to prevent data destruction
Split-brain
Split-brain is a lay term to describe the result when the corpus callosum connecting the two hemispheres of the brain is severed to some degree. The surgical operation to produce this condition is called corpus callosotomy and is usually used as a last resort to treat otherwise intractable epilepsy...
syndrome, occurs when two parts of a computer cluster are disconnected, each part believing that the other is no longer running.
High-availability cluster
High-availability cluster
High-availability clusters are groups of computers that support server applications that can be reliably utilized with a minimum of down-time. They operate by harnessing redundant computers in groups or clusters that provide continued service when system components fail...
s usually use a heartbeat private network
Heartbeat private network
In computer clusters, heartbeat network is a private network which is shared only by the cluster nodes, and is not accessible from outside the cluster. It is used by cluster nodes in order to monitor each node's status and communicate with each other....
connection which is used to monitor the health and status of each node in the cluster. One subtle, but serious condition every clustering software must be able to handle is split-brain.
Split-brain occurs when all of the private links go down simultaneously, but the cluster nodes are still running.
If that happens, each node in the cluster may mistakenly decide that every other node has gone down and attempt to start services that other nodes are still running. Having duplicate instances of services may cause data corruption
Data corruption
Data corruption refers to errors in computer data that occur during writing, reading, storage, transmission, or processing, which introduce unintended changes to the original data...
on the shared storage.
This problem can lead to data inconsistency. To prevent it computers should use redundant communications and fall down to an auto-fencing
Fencing (computing)
Fencing is the process of isolating a node of a computer cluster when the former is malfunctioning. Isolating a node means ensuring that I/O can no longer be done from it. Fencing is typically done automatically, by cluster infrastructure such as shared disk file systems, in order to protect...
mode when the peers look like they are down. This means they should run in a limited mode to prevent data destruction