Storage Foundation for Sybase ASE CE 7.4 Administrator's Guide - Linux
- Overview of Storage Foundation for Sybase ASE CE
- About Storage Foundation for Sybase ASE CE
- About SF Sybase CE components
- About optional features in SF Sybase CE
- Administering SF Sybase CE and its components
- Administering SF Sybase CE
- Starting or stopping SF Sybase CE on each node
- Administering VCS
- Administering I/O fencing
- About the vxfentsthdw utility
- Testing the coordinator disk group using the -c option of vxfentsthdw
- About the vxfenadm utility
- About the vxfenclearpre utility
- About the vxfenswap utility
- Administering CVM
- Changing the CVM master manually
- Administering CFS
- Administering the Sybase agent
- Administering SF Sybase CE
- Troubleshooting SF Sybase CE
- About troubleshooting SF Sybase CE
- Troubleshooting I/O fencing
- Fencing startup reports preexisting split-brain
- Troubleshooting Cluster Volume Manager in SF Sybase CE clusters
- Troubleshooting interconnects
- Troubleshooting Sybase ASE CE
- Prevention and recovery strategies
- Prevention and recovery strategies
- Managing SCSI-3 PR keys in SF Sybase CE cluster
- Prevention and recovery strategies
- Tunable parameters
- Appendix A. Error messages
About coordination points
Coordination points provide a lock mechanism to determine which nodes get to fence off data drives from other nodes. A node must eject a peer from the coordination points before it can fence the peer from the data drives. Racing for control of the coordination points to fence data disks is the key to understand how fencing prevents split-brain.
Disks that act as coordination points are called coordinator disks. Coordinator disks are three standard disks or LUNs set aside for I/O fencing during cluster reconfiguration. Coordinator disks do not serve any other storage purpose in the SF Sybase CE configuration.
You can configure coordinator disks to use Veritas Volume Manager Dynamic Multi-pathing (DMP) feature. Dynamic Multi-pathing (DMP) allows coordinator disks to take advantage of the path failover and the dynamic adding and removal capabilities of DMP. So, you can configure I/O fencing to use either DMP devices or the underlying raw character devices. I/O fencing uses SCSI-3 disk policy that is either raw or dmp based on the disk device that you use. The disk policy is raw by default. Veritas recommends using the DMP disk policy.
See the Storage Foundation Administrator's Guide.