Building an Extended Distance Cluster Using Serviceguard and Software RAID
Two Data Center and Quorum Service Location Architectures
•Fibre Channel Direct Fabric Attach (DFA) is recommended over Fibre Channel Arbitrated loop configurations, due to the superior performance of DFA, especially as the distance increases. Therefore Fibre Channel switches are recommended over Fibre Channel hubs.
•Any combination of the following Fibre Channel capable disk arrays may be used: HP StorageWorks 1000 and 1500 series Modular Storage Arrays, HP StorageWorks Enterprise Virtual Arrays, or HP StorageWorks Disk Array XP.
•For disaster tolerance, application data must be mirrored between the primary data centers. You must ensure that the mirror copies reside in different data centers, as the software cannot determine the locations.
NOTE | When a failure results in the mirror copies losing synchronization, |
| MD will perform a full resynchronization when both halves of the |
| mirror are available. |
|
|
•No routing is allowed for the networks between data centers. Routing is allowed to the third data center if a Quorum Server is used in that data center.
The following is a list of recommended arbitration methods for Extended Distance Cluster solutions in order of preference:
•Quorum Server running in a Serviceguard cluster
•Quorum Server
For more information on Quorum Server, see the Serviceguard Quorum Server Release Notes for Linux.
Figure 2-1 is an example of a two data center and third location configuration using DWDM, with a quorum server node on the third site.
54 | Chapter 2 |
