Here the resource groups are the same as the ones in the mutual takeover configuration. Also, similar to the previous configuration, nodes 1 and 2 each have priorities of 1 for one of the resource groups, A or B. The only thing different in this configuration is that there is a third node which has a priority of 2 for both the resource groups.
During normal operations, node 3 is either idle or is providing
So, in this configuration, you are protected against the failure of two nodes and there is no performance degradation after the failure of one node.
2.4.2.2 Concurrent Disk Access Configurations
A concurrent disk access configuration usually has all its disk storage defined as part of one concurrent resource group. The nodes associated with a concurrent resource group have no priorities assigned to them.
If a 7135 RAIDiant Array Subsystem is used for storage, you can have a maximum of four nodes concurrently accessing a set of storage resources. If you are using the 7133 SSA Disk Subsystem, you can have up to eight nodes concurrently accessing it.This is because of the physical characteristics of SCSI versus SSA.
In the case of a node failure, a concurrent resource group is not explicitly taken over by any other node, since it is already active on the other nodes. However, in order to somewhat mask a node failure from the end users, you should also have cascading resource groups, each containing the service IP address for each node in the cluster. When a node fails, its service IP address will be taken over by another node and users can continue to access critical services at the same IP address that they were using before the node failed.
2.4.3 IP Address Takeover
The goal of IP Address Takeover is to make the server’s service address highly available and to give clients the possibility of always connecting to the same IP address. In order to achieve this, you must do the following:
•Decide which types of networks and
