Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 56)

Logical chassis cluster mode characteristics
The following are the main characteristics of logical chassis cluster mode:
• The maximum number of nodes supported in a logical chassis cluster is 24 for the Brocade VDX
6710, 6720, and 6730; the maximum is 32 for the Brocade VDX 6740, 6740T, 6740T-1G, and 8770.
• Physical connectivity requirements for logical chassis cluster deployment are the same as those for
fabric cluster deployment.
• A single global configuration exists across all nodes, while each node can contain its unique local
configuration. However, each node contains the local configuration information for all other nodes in
the cluster.
• Global and local configurations for the entire logical chassis cluster is performed from one node —
the principal node only.
• Startup configurations are not maintained by the cluster; each node preserves its running
configuration.
• A logical chassis cluster can be transitioned into a fabric cluster while preserving configurations if
you follow the steps provided later in this section
• An existing fabric cluster can be transitioned into a logical chassis cluster while preserving
configurations if you follow the steps provided later in this section
• A node that is a member of a logical chassis cluster can be transitioned to standalone mode.
Platforms that allow standalone mode are the Brocade VDX 6710-54, 6720, and 6730.
• Cluster-wide firmware upgrades can be performed.
• Cluster-wide supportSave can be performed.
Command blocking in logical chassis cluster mode
In logical chassis cluster mode, some commands cannot be run while other commands or events are
processing.
If one of the following CLI command types or events is in progress in the cluster, then any one of the
CLI command types listed below will be rejected until the current command or event has finished.
1. Copy file running-config commands
2. HA failover commands
3. VCS ID/RbridgeID change commands
4. Cluster mode change from logical chassis cluster to fabric cluster
5. Copy default-config startup-config commands
6. Configuration updates by individual commands
7. Cluster formation events, such as initial cluster formation or secondary joining or rejoining of a
cluster
These command and events are considered to be blocked from occurring simultaneously. However, if
the principal node changes during one of these operations or HA failover occurs on principal switch,
the new principal will not retain the information that the commands or events not in progress are in a
blocked state.
In the case of commands being blocked, the following are some of the error messages that could
result:
• Cluster formation is in progress. Please try again later.
• User Configuration update is in progress. Please try again later.
• Configuration file replay is in progress. Please try again later.
• HA failover is in progress in the cluster. Please try again later.
• VCS Config change is in progress in the cluster. Please try again later.
• Copy default-config startup-config is in progress. Please try again later.
Logical chassis cluster mode characteristics
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