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3.4. Global Cluster Properties
When a cluster is created, or if you select a cluster to configure, a cluster-specific page is displayed. The page provides an interface for configuring cluster-wide properties and detailed properties. You can configure cluster-wide properties with the tabbed interface below the cluster name. The interface provides the following tabs:
, , , and . To configure the parameters in those tabs, follow the steps in this section. If you do not need to configure parameters in a tab, skip the step for that tab.
- Thetext box displays the cluster name; it does not accept a cluster name change. You cannot change the cluster name. The only way to change the name of a Red Hat cluster is to create a new cluster configuration with the new name.
- Thevalue is set to
1
by default and is automatically incremented each time you modify your cluster configuration. However, if you need to set it to another value, you can specify it at the text box. - You can enter advanced cluster properties by clicking. Clicking reveals a list of advanced properties. You can click any advanced property for online help about the property.
Enter the values required and clickfor changes to take effect.- Theparameter is the number of seconds the fence daemon (
fenced
) waits before fencing a node (a member of the fence domain) after the node has failed. The default value is0
. Its value may be varied to suit cluster and network performance. - Theparameter is the number of seconds the fence daemon (
fenced
) waits before fencing a node after the node joins the fence domain. The default value is3
. A typical setting for is between 20 and 30 seconds, but can vary according to cluster and network performance.
Enter values required and Clickfor changes to take effect.Note
For more information about fenced(8) man page.and , refer to theNote
IPV6 is not supported for Cluster Suite in Red Hat Enterprise Linux 5.If you do not specify a multicast address, the Red Hat Cluster software (specifically,cman
, the Cluster Manager) creates one. It forms the upper 16 bits of the multicast address with 239.192 and forms the lower 16 bits based on the cluster ID.Note
The cluster ID is a unique identifier thatcman
generates for each cluster. To view the cluster ID, run thecman_tool status
command on a cluster node.If you do specify a multicast address, you should use the 239.192.x.x series thatcman
uses. Otherwise, using a multicast address outside that range may cause unpredictable results. For example, using 224.0.0.x (which is "All hosts on the network") may not be routed correctly, or even routed at all by some hardware.Note
If you specify a multicast address, make sure that you check the configuration of routers that cluster packets pass through. Some routers may take a long time to learn addresses, seriously impacting cluster performance.- Table 3.1, “Quorum-Disk Parameters” describes the parameters. If you need to use a quorum disk, click , enter quorum disk parameters, click , and restart the cluster for the changes to take effect.tab — This tab provides an interface for configuring these parameters: , , , , , , , , and . The parameter is enabled by default.
Important
Quorum-disk parameters and heuristics depend on the site environment and the special requirements needed. To understand the use of quorum-disk parameters and heuristics, refer to the qdisk(5) man page. If you require assistance understanding and using quorum disk, contact an authorized Red Hat support representative.Note
Clickingon the tab propagates changes to the cluster configuration file (/etc/cluster/cluster.conf
) in each cluster node. However, for the quorum disk to operate, you must restart the cluster (refer to Section 4.1, “Starting, Stopping, and Deleting Clusters”).
Parameter | Description | |||
---|---|---|---|---|
Disables quorum partition. Disables quorum-disk parameters in the | tab.||||
Enables quorum partition. Enables quorum-disk parameters in the | tab.||||
The frequency of read/write cycles, in seconds. | ||||
The number of votes the quorum daemon advertises to CMAN when it has a high enough score. | ||||
The number of cycles a node must miss to be declared dead. | ||||
The minimum score for a node to be considered "alive". If omitted or set to 0, the default function, floor((n+1)/2) , is used, where n is the sum of the heuristics scores. The value must never exceed the sum of the heuristic scores; otherwise, the quorum disk cannot be available. | ||||
The storage device the quorum daemon uses. The device must be the same on all nodes. | ||||
Specifies the quorum disk label created by the mkqdisk utility. If this field contains an entry, the label overrides the field. If this field is used, the quorum daemon reads /proc/partitions and checks for qdisk signatures on every block device found, comparing the label against the specified label. This is useful in configurations where the quorum device name differs among nodes. | ||||
| ||||
Propagates the changes to the cluster configuration file (/etc/cluster/cluster.conf ) in each cluster node. |