Stonith shoot the node the head

Chapter 7 ■ Managing and OptiMizing a COMplex raC envirOnMent

Split-Brain Scenarios and How to Avoid Them

Split-brain situations generally translate into a painful experience for the business and IT organizations, mainly because of the unplanned downtime and the corresponding impact on the business involved. Figure 7-9 shows a typical split-brain scenario:

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Chapter 7 ■ Managing and OptiMizing a COMplex raC envirOnMent

•� Ensure that any kind of antivirus software is not active/present on any of the RAC nodes of the cluster. This can interfere with the internal workings of the LMS and other RAC processes and try to block normal activity by them; in turn, this can result in excessive usage of CPU, ultimately being driven all the way to 100% CPU consumption, resulting in RAC nodes being unresponsive and thereby evicted from the cluster.

•� Patch to the latest versions of the Oracle Database software. Many bugs have been associated with various versions that are known to cause split-brain scenarios to occur. Staying current with the latest CPU/PSUs is known to mitigate stability/performance issues.