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

120 Setting up I/O fencingAbout the vxfenadm utilityTable 5-5I/O fencing scenariosEvent Node A: What Node B: What Operator actionhappens?happens?The diskarraycontainingtwo of thethreecoordinatordisks ispowered off.Node A continues tooperate as long as nonodes leave the cluster.Node B continues tooperate as long as nonodes leave thecluster.Node B leavesthe clusterand the diskarray is stillpowered off.Node A races for amajority of coordinatordisks. Node A failsbecause only one ofthree coordinator disksis available. Node Aremoves itself from thecluster.Node B leaves thecluster.Power on failed diskarray and restart I/Ofencing driver toenable Node A toregister with allcoordinator disks.About the vxfenadm utilityAdministrators can use the vxfenadm command to troubleshoot and test fencingconfigurations. The command’s options for use by administrators are:-g read and display keys-i read SCSI inquiry information from device-m register with disks-n make a reservation with disks-p remove registrations made by other systems-r read reservations-x remove registrations

Setting up I/O fencingAbout the vxfenadm utility121Registration key formattingThe key defined by VxVM associated with a disk group consists of seven bytesmaximum. This key becomes unique among the systems when the VxVMprefixes it with the ID of the system. The key used for I/O fencing, therefore,consists of eight bytes.0 7NodeIDVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedThe keys currently assigned to disks can be displayed by using the vxfenadmcommand. For example, from the system with node ID 1, display the key for the disk /dev/rdsk/c2t1d0s2 by entering:# vxfenadm -g /dev/rdsk/c2t1d0s2Reading SCSI Registration Keys...Device Name: /dev/rdsk/c2t1d0s2Total Number of Keys: 1key[0]:Key Value [Numeric Format]: 65,45,45,45,45,45,45,45Key Value [Character Format]: A------­The -g option of vxfenadm displays all eight bytes of a key value in two formats.In the numeric format, the first byte, representing the Node ID, contains thesystem ID plus 65. The remaining bytes contain the ASCII values of the letters ofthe key, in this case, “-------”. In the next line, the node ID 0 is expressed as “A;”node ID 1 would be “B.”

Setting up I/O fencingAbout the vxfenadm utility121Registration key <strong>for</strong>mattingThe key defined by VxVM associated with a disk group consists of seven bytesmaximum. This key becomes unique among the systems when the VxVMprefixes it with the ID of the system. The key used <strong>for</strong> I/O fencing, there<strong>for</strong>e,consists of eight bytes.0 7NodeIDVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedVxVMDefinedThe keys currently assigned to disks can be displayed by using the vxfenadmcommand. For example, from the system with node ID 1, display the key <strong>for</strong> the disk /dev/rdsk/c2t1d0s2 by entering:# vxfenadm -g /dev/rdsk/c2t1d0s2Reading SCSI Registration Keys...Device Name: /dev/rdsk/c2t1d0s2Total Number of Keys: 1key[0]:Key Value [Numeric Format]: 65,45,45,45,45,45,45,45Key Value [Character Format]: A------­The -g option of vxfenadm displays all eight bytes of a key value in two <strong>for</strong>mats.In the numeric <strong>for</strong>mat, the first byte, representing the Node ID, contains thesystem ID plus 65. The remaining bytes contain the ASCII values of the letters ofthe key, in this case, “-------”. In the next line, the node ID 0 is expressed as “A;”node ID 1 would be “B.”

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