4.5.5. Quorum Disk Configuration
4.5.5. Quorum Disk Configuration Clicking on the QDisk tab displays the Quorum Disk Configuration page, which provides an interface for configuring quorum disk parameters if you need to use a quorum disk. Note 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, see the qdisk (5) man page. If you require assistance understanding and using quorum disk, contact an authorized Red Hat support representative. The Do Not Use a Quorum Disk parameter is enabled by default. If you need to use a quorum disk, click Use a Quorum Disk , enter the quorum disk parameters, and click Apply . You must restart the cluster for the changes to take effect. Table 4.1, "Quorum-Disk Parameters" describes the quorum disk parameters. Table 4.1. Quorum-Disk Parameters Parameter Description Specify Physical Device: By Device Label Specifies the quorum disk label created by the mkqdisk utility. If this field is used, the quorum daemon reads the /proc/partitions file 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. Heuristics Path to Program - The program used to determine if this heuristic is available. This can be anything that can be executed by /bin/sh -c . A return value of 0 indicates success; anything else indicates failure. This field is required. Interval - The frequency (in seconds) at which the heuristic is polled. The default interval for every heuristic is 2 seconds. Score - The weight of this heuristic. The default score for each heuristic is 1. TKO - The number of consecutive failures required before this heuristic is declared unavailable. Minimum Total Score 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 Minimum Total Score value must never exceed the sum of the heuristic scores; otherwise, the quorum disk cannot be available. Note Clicking Apply on the QDisk Configuration tab propagates changes to the cluster configuration file ( /etc/cluster/cluster.conf ) in each cluster node. However, for the quorum disk to operate or for any modifications you have made to the quorum disk parameters to take effect, you must restart the cluster (see Section 5.4, "Starting, Stopping, Restarting, and Deleting Clusters" ), ensuring that you have restarted the qdiskd daemon on each node.