LLT and GAB
VCS uses two components, LLT and GAB, to share data over private networks among systems. These components provide the performance and reliability that VCS requires.
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LLT (Low Latency Transport) provides fast, kernel-to-kernel communications, and monitors network connections. The system administrator configures LLT by creating the configuration files /etc/llthosts, which lists all the nodes in the cluster, and /etc/llttab, which describes the local system's private network links to the other nodes in the cluster.
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GAB (Group Membership and Atomic Broadcast) provides the global message order required to maintain a synchronized state among the nodes. It monitors disk communications such as the VCS heartbeat utility. The system administrator configures the GAB driver by creating a configuration file (/etc/gabtab).
See Verifying LLT and GAB configuration files.
