AIX for System Administrators 2020-04-01 17:03:00

Resource, Resource Group Resources: File systems, service IPs, applications… which are highly available (These can be moved from one node to another.)Resource Group (RG): Those resources which are grouped together, and moved together during a failoverDefault node priority: The order in which the nodes are defined in the RG. A RG with default attributes will move from node to node in this order as each node fails.Home node: The highest priority node in the default node list. RG will initially be activated there. (It is not the node where the RG is currently active on.)Fallover: The process of moving a RG that is online on one node to another node in the cluster in response to an event.Fallback: The process of moving a RG that is currently online on a node that is not its home node, to a re-integrating node.Node failure: If a node fails, the RGs that were active on that node are distributed among the other nodes in the cluster, depending on their fallover policies.Node recovery: When a node recovers and is reintegrated into the cluster, RGs can be reacquired depending on their fallback policies.————————————Resource group (RG)Resource groups allow PowerHA to manage resources as a single entity. For example, an application can consist of start and stop scripts, a database, and an IP address. These resources are then included in a resource group for PowerHA to control as a single entity. PowerHA ensures that resource groups remain highly available by moving them from node to node.Resource group states:- Online: The RG is currently operating properly on one or more nodes in the cluster.- Offline: The RG is not operating and currently not in error condition (the user may requested this state or dependencies were not met)- Acquiring: A RG is currently coming up on a node. In normal conditions status changes to Online.- Releasing: The RG is in the process of being released (going down). In normal conditions after released, the status changes to offline.- Error: The resource group has reported an error condition. User interaction is required.- Unknown: The RG’s current status cannot be obtained, possibly because of loss of communication, or a resource group dependency is not met…Each node that joins the cluster automatically attempts to bring online any of the resource groups that are in the ERROR state.Start up options:- Online on home node only: The RG is brought online when its home node joins the cluster. If home node isn’t available, it stays offline- Online on first available node: The RG is brought online when the first node in its node list joins the cluster.- Online on all available nodes: The RG is brought online on all nodes in its node list as they join the cluster.- Online using distribution policy: The RG is brought online only if the node has no other resource group of this type already online.Fallover options:- Fall over to next priority node in list: The RG falls over to the next node in the resource group node list.- Fallover…

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