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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: , (GULM clusters only), (DLM clusters only), (DLM clusters only), and (DLM clusters only). 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.
- tab — This tab displays cluster name and provides an interface for configuring the configuration version and advanced cluster properties. The parameters are summarized as follows:
- The text 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.
- The value is set to
1by 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 click for changes to take effect. - tab (DLM clusters only) — This tab provides an interface for configuring these parameters: and . The parameters are summarized as follows:
- The parameter 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. - The parameter 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 Click for changes to take effect.Note
For more information about and , refer to the fenced(8) man page. - tab (GULM clusters only) — This tab provides an interface for configuring GULM lock servers. The tab indicates each node in a cluster that is configured as a GULM lock server and provides the capability to change lock servers. Follow the rules provided at the tab for configuring GULM lock servers and click for changes to take effect.
Important
The number of nodes that can be configured as GULM lock servers is limited to either one, three, or five. - tab (DLM clusters only) — This tab provides an interface for configuring these parameters: and . specifies whether a multicast address is used for cluster management communication among cluster nodes. is the default setting. To use a multicast address for cluster management communication among cluster nodes, click . When is selected, the and text boxes are enabled. If is selected, enter the multicast address into the text box and the multicast network interface into the text box. Click for changes to take effect.
- tab (DLM clusters only) — This tab provides an interface for configuring these parameters: , , , , , , , , and . The parameter is enabled by default. 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.
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
Clicking on 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. |
