Veritas InfoScale™ 7.3.1 Troubleshooting Guide - Solaris
- Introduction
- Section I. Troubleshooting Veritas File System
- Section II. Troubleshooting Veritas Volume Manager
- Recovering from hardware failure
- Failures on RAID-5 volumes
- Recovery from failure of a DCO volume
- Recovering from instant snapshot failure
- Recovering from failed vxresize operation
- Recovering from boot disk failure
- Hot-relocation and boot disk failure
- Recovery from boot failure
- Repair of root or /usr file systems on mirrored volumes
- Replacement of boot disks
- Recovery by reinstallation
- Managing commands, tasks, and transactions
- Backing up and restoring disk group configurations
- Troubleshooting issues with importing disk groups
- Recovering from CDS errors
- Logging and error messages
- Troubleshooting Veritas Volume Replicator
- Recovery from configuration errors
- Errors during an RLINK attach
- Errors during modification of an RVG
- Recovery on the Primary or Secondary
- Recovering from Primary data volume error
- Primary SRL volume error cleanup and restart
- Primary SRL header error cleanup and recovery
- Secondary data volume error cleanup and recovery
- Troubleshooting issues in cloud deployments
- Recovering from hardware failure
- Section III. Troubleshooting Dynamic Multi-Pathing
- Section IV. Troubleshooting Storage Foundation Cluster File System High Availability
- Troubleshooting Storage Foundation Cluster File System High Availability
- Troubleshooting CFS
- Troubleshooting fenced configurations
- Troubleshooting Cluster Volume Manager in Veritas InfoScale products clusters
- Troubleshooting Storage Foundation Cluster File System High Availability
- Section V. Troubleshooting Cluster Server
- Troubleshooting and recovery for VCS
- VCS message logging
- Gathering VCS information for support analysis
- Troubleshooting the VCS engine
- Troubleshooting Low Latency Transport (LLT)
- Troubleshooting Group Membership Services/Atomic Broadcast (GAB)
- Troubleshooting VCS startup
- Troubleshooting service groups
- Troubleshooting resources
- Troubleshooting I/O fencing
- System panics to prevent potential data corruption
- Fencing startup reports preexisting split-brain
- Troubleshooting CP server
- Troubleshooting server-based fencing on the Veritas InfoScale products cluster nodes
- Issues during online migration of coordination points
- Troubleshooting notification
- Troubleshooting and recovery for global clusters
- Troubleshooting licensing
- Licensing error messages
- VCS message logging
- Troubleshooting and recovery for VCS
- Section VI. Troubleshooting SFDB
Fencing startup reports preexisting split-brain
The vxfen driver functions to prevent an ejected node from rejoining the cluster after the failure of the private network links and before the private network links are repaired.
For example, suppose the cluster of system 1 and system 2 is functioning normally when the private network links are broken. Also suppose system 1 is the ejected system. When system 1 restarts before the private network links are restored, its membership configuration does not show system 2; however, when it attempts to register with the coordinator disks, it discovers system 2 is registered with them. Given this conflicting information about system 2, system 1 does not join the cluster and returns an error from vxfenconfig that resembles:
vxfenconfig: ERROR: There exists the potential for a preexisting split-brain. The coordinator disks list no nodes which are in the current membership. However, they also list nodes which are not in the current membership. I/O Fencing Disabled!
Also, the following information is displayed on the console:
<date> <system name> vxfen: WARNING: Potentially a preexisting <date> <system name> split-brain. <date> <system name> Dropping out of cluster. <date> <system name> Refer to user documentation for steps <date> <system name> required to clear preexisting split-brain. <date> <system name> <date> <system name> I/O Fencing DISABLED! <date> <system name> <date> <system name> gab: GAB:20032: Port b closed
However, the same error can occur when the private network links are working and both systems go down, system 1 restarts, and system 2 fails to come back up. From the view of the cluster from system 1, system 2 may still have the registrations on the coordination points.
Assume the following situations to understand preexisting split-brain in server-based fencing:
There are three CP servers acting as coordination points. One of the three CP servers then becomes inaccessible. While in this state, one client node leaves the cluster, whose registration cannot be removed from the inaccessible CP server. When the inaccessible CP server restarts, it has a stale registration from the node which left the VCS. In this case, no new nodes can join the cluster. Each node that attempts to join the cluster gets a list of registrations from the CP server. One CP server includes an extra registration (of the node which left earlier). This makes the joiner node conclude that there exists a preexisting split-brain between the joiner node and the node which is represented by the stale registration.
All the client nodes have crashed simultaneously, due to which fencing keys are not cleared from the CP servers. Consequently, when the nodes restart, the vxfen configuration fails reporting preexisting split brain.
These situations are similar to that of preexisting split-brain with coordinator disks, where you can solve the problem running the vxfenclearpre command. A similar solution is required in server-based fencing using the cpsadm command.