> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/gridgain/gridgain-9/architecture/cluster.md).

# Cluster

How a GridGain 9 cluster is built and run — node components and request flow, RAFT consensus, cluster initialization and lifecycle, and fault tolerance.

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[Cluster Architecture](/docs/gridgain/gridgain-9/architecture/cluster/cluster-architecture.md)
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A deeper look at the GridGain 9 system architecture: node components, cluster coordination, RAFT replication, transaction processing, and query execution.
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[RAFT Consensus](/docs/gridgain/gridgain-9/architecture/cluster/raft-consensus.md)
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How GridGain 9 uses the RAFT consensus algorithm to maintain data consistency and fault tolerance across the cluster.
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[Cluster Lifecycle](/docs/gridgain/gridgain-9/architecture/cluster/cluster-lifecycle.md)
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How a GridGain 9 cluster is initialized and how its lifecycle works, including topology, cluster initialization, system groups, and node join scenarios.
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[Cluster Fault Tolerance](/docs/gridgain/gridgain-9/architecture/cluster/cluster-fault-tolerance.md)
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Fault tolerance characteristics of GridGain 9 cluster components, what happens during failure scenarios, and how to plan for high availability.
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