Cluster Logical Volume Manager - Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 4.6 Overview

Cluster Logical Volume Manager

Figure 1.14. GFS and GNBD with Directly Connected Storage
6. Cluster Logical Volume Manager
The Cluster Logical Volume Manager (CLVM) provides a cluster-wide version of LVM2. CLVM
provides the same capabilities as LVM2 on a single node, but makes the volumes available to
all nodes in a Red Hat cluster. The logical volumes created with CLVM make logical volumes
available to all nodes in a cluster.
The key component in CLVM is . is a daemon that provides clustering extensions
clvmd clvmd
to the standard LVM2 tool set and allows LVM2 commands to manage shared storage.
clvmd
runs in each cluster node and distributes LVM metadata updates in a cluster, thereby
presenting each cluster node with the same view of the logical volumes (refer to Figure 1.15,
"CLVM Overview"). Logical volumes created with CLVM on shared storage are visible to all
nodes that have access to the shared storage. CLVM allows a user to configure logical volumes
on shared storage by locking access to physical storage while a logical volume is being
configured. CLVM uses the lock-management service provided by the cluster infrastructure
(refer to Section 3, "Cluster Infrastructure").
Note
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