About network failure and GAB IOFENCE message

If a network partition occurs, a cluster can split into two or more separate sub-clusters. When two clusters join as one, GAB ejects one sub-cluster. GAB prints diagnostic messages and sends iofence messages to the sub-cluster being ejected.

The systems in the sub-cluster process the iofence messages depending on the type of GAB port that a user client process or a kernel module uses:

The gabconfig command's -k and -j options apply to the user client processes. The -k option prevents GAB from panicking the system when it cannot kill the user processes. The -j option panics the system and does not kill the user process when GAB receives the iofence message.