Running Lvm In A Cluster - Red Hat ENTERPRISE LINUX 4 - LVM ADMINISTRATOR Manual

1.3. Running LVM in a Cluster

The Clustered Logical Volume Manager (CLVM) is a set of clustering extensions to LVM. These
extensions allow a cluster of computers to manage shared storage (for example, on a SAN) using
LVM.
The clmvd daemon is the key clustering extension to LVM. The clvmd daemon runs in each cluster
computer and distributes LVM metadata updates in a cluster, presenting each cluster computer with
the same view of the logical volumes.
Figure 1.2, "CLVM Overview"
Figure 1.2. CLVM Overview
Logical volumes created with CLVM on shared storage are visible to all computers 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 locking services provided by the
high availability symmetric infrastructure.
Note
Shared storage for use in Red Hat Cluster Suite requires that you be running the cluster
logical volume manager daemon (clvmd) or the High Availability Logical Volume
Management agents (HA-LVM). If you are not able to use either the clvmd daemon or
HA-LVM for operational reasons or because you do not have the correct entitlements, you
shows a CLVM overview in a Red Hat cluster.
Running LVM in a Cluster
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