Cluster Server Installation Guide for Solaris x64 5.0 - Storage ...

Cluster Server Installation Guide for Solaris x64 5.0 - Storage ... Cluster Server Installation Guide for Solaris x64 5.0 - Storage ...

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13.07.2015 Views

124 Setting up I/O fencingTroubleshooting I/O fencingregistered with them. Given this conflicting information about system 2,system 1 does not join the cluster and returns an error from vxfenconfig thatresembles: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: vxfen: WARNING: Potentially a preexisting split-brain. Dropping out of cluster. Refer to user documentation for steps required to clear preexisting split-brain. I/O Fencing DISABLED! gab: GAB:20032: Port b closedHowever, the same error can occur when the private network links are workingand both systems go down, system 1 restarts, and system 2 fails to come backup. From the view of the cluster from system 1, system 2 may still have theregistrations on the coordinator disks.Case 1: system 2 up, system 1 ejected(actual potential split brain)Determine if system1 is up or not. If it is up and running, shut it down and repairthe private network links to remove the split brain condition. restart system 1.Case 2: system 2 down, system 1 ejected(apparent potential split brain)1 Physically verify that system 2 is down.2 Verify the systems currently registered with the coordinator disks. Use thefollowing command:# vxfenadm -g all -f /etc/vxfentabThe output of this command identifies the keys registered with thecoordinator disks.3 Clear the keys on the coordinator disks as well as the data disks using thecommand /opt/VRTSvcs/rac/bin/vxfenclearpre.See “Clearing keys after split brain using vxfenclearpre command” onpage 125.4 Make any necessary repairs to system 2 and restart.

Setting up I/O fencingTroubleshooting I/O fencing125Clearing keys after split brain using vxfenclearpre commandWhen you have encountered a split brain condition, use the vxfenclearprecommand to remove SCSI-3 registrations and reservations on the coordinatordisks as well as on the data disks in all shared disk groups.To clear keys after split brain1 Shut down all other nodes in the cluster that have access to the sharedstorage. This prevents data corruption.2 Start the script:# cd /opt/VRTSvcs/vxfen/bin# ./vxfenclearpre3 Read the script’s introduction and warning. Then, you can choose to let thescript run.Do you still want to continue: [y/n] (default : n) yInformational messages resembling the following may appear on theconsole of one of the nodes in the cluster when a node is ejected from a disk/LUN: scsi: WARNING: /sbus@3,0/lpfs@0,0/sd@0,1(sd91): Error for Command: Error Level: Informational scsi: Requested Block: 0 Error Block 0 scsi: Vendor: Serial Number: 0400759B006E scsi: Sense Key: Unit Attention scsi: ASC: 0x2a (), ASCQ: 0x4, FRU: 0x0These informational messages may be ignored.Cleaning up the coordinator disks...Cleaning up the data disks for all shared disk groups...Successfully removed SCSI-3 persistent registration and reservations from the coordinator disks as well as the shared data disks.Reboot the server to proceed with normal cluster startup...#4 Restart all nodes in the cluster.Adding or removing coordinator disksReview the following information to:■Replace coordinator disk in the coordinator disk group

124 Setting up I/O fencingTroubleshooting I/O fencingregistered with them. Given this conflicting in<strong>for</strong>mation about system 2,system 1 does not join the cluster and returns an error from vxfenconfig thatresembles:vxfenconfig: ERROR: There exists the potential <strong>for</strong> 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 in<strong>for</strong>mation is displayed on the console: vxfen: WARNING: Potentially a preexisting split-brain. Dropping out of cluster. Refer to user documentation <strong>for</strong> steps required to clear preexisting split-brain. I/O Fencing DISABLED! gab: GAB:20032: Port b closedHowever, the same error can occur when the private network links are workingand both systems go down, system 1 restarts, and system 2 fails to come backup. From the view of the cluster from system 1, system 2 may still have theregistrations on the coordinator disks.Case 1: system 2 up, system 1 ejected(actual potential split brain)Determine if system1 is up or not. If it is up and running, shut it down and repairthe private network links to remove the split brain condition. restart system 1.Case 2: system 2 down, system 1 ejected(apparent potential split brain)1 Physically verify that system 2 is down.2 Verify the systems currently registered with the coordinator disks. Use thefollowing command:# vxfenadm -g all -f /etc/vxfentabThe output of this command identifies the keys registered with thecoordinator disks.3 Clear the keys on the coordinator disks as well as the data disks using thecommand /opt/VRTSvcs/rac/bin/vxfenclearpre.See “Clearing keys after split brain using vxfenclearpre command” onpage 125.4 Make any necessary repairs to system 2 and restart.

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