Cluster Server 7.4.1 Administrator's Guide - Linux
- Section I. Clustering concepts and terminology
- Introducing Cluster Server
- About Cluster Server
- About cluster control guidelines
- About the physical components of VCS
- Logical components of VCS
- Types of service groups
- About resource monitoring
- Agent classifications
- About cluster control, communications, and membership
- About security services
- Components for administering VCS
- About cluster topologies
- VCS configuration concepts
- Introducing Cluster Server
- Section II. Administration - Putting VCS to work
- About the VCS user privilege model
- Administering the cluster from the command line
- About administering VCS from the command line
- About installing a VCS license
- Administering LLT
- Starting VCS
- Stopping the VCS engine and related processes
- Logging on to VCS
- About managing VCS configuration files
- About managing VCS users from the command line
- About querying VCS
- About administering service groups
- Modifying service group attributes
- About administering resources
- Enabling and disabling IMF for agents by using script
- Linking and unlinking resources
- About administering resource types
- About administering clusters
- Configuring applications and resources in VCS
- VCS bundled agents for UNIX
- Configuring NFS service groups
- About NFS
- Configuring NFS service groups
- Sample configurations
- About configuring the RemoteGroup agent
- About configuring Samba service groups
- About testing resource failover by using HA fire drills
- Predicting VCS behavior using VCS Simulator
- Section III. VCS communication and operations
- About communications, membership, and data protection in the cluster
- About cluster communications
- About cluster membership
- About membership arbitration
- About membership arbitration components
- About server-based I/O fencing
- About majority-based fencing
- About the CP server service group
- About secure communication between the VCS cluster and CP server
- About data protection
- Examples of VCS operation with I/O fencing
- About cluster membership and data protection without I/O fencing
- Examples of VCS operation without I/O fencing
- 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
- About administering the coordination point server
- About configuring a CP server to support IPv6 or dual stack
- About migrating between disk-based and server-based fencing configurations
- Migrating between fencing configurations using response files
- Controlling VCS behavior
- VCS behavior on resource faults
- About controlling VCS behavior at the service group level
- About AdaptiveHA
- Customized behavior diagrams
- About preventing concurrency violation
- VCS behavior for resources that support the intentional offline functionality
- VCS behavior when a service group is restarted
- About controlling VCS behavior at the resource level
- VCS behavior on loss of storage connectivity
- Service group workload management
- Sample configurations depicting workload management
- The role of service group dependencies
- About communications, membership, and data protection in the cluster
- Section IV. Administration - Beyond the basics
- VCS event notification
- VCS event triggers
- Using event triggers
- List of event triggers
- Virtual Business Services
- Section V. Veritas High Availability Configuration wizard
- Introducing the Veritas High Availability Configuration wizard
- Administering application monitoring from the Veritas High Availability view
- Administering application monitoring from the Veritas High Availability view
- Administering application monitoring from the Veritas High Availability view
- Section VI. Cluster configurations for disaster recovery
- Connecting clusters–Creating global clusters
- VCS global clusters: The building blocks
- About global cluster management
- About serialization - The Authority attribute
- Prerequisites for global clusters
- Setting up a global cluster
- About IPv6 support with global clusters
- About cluster faults
- About setting up a disaster recovery fire drill
- Test scenario for a multi-tiered environment
- Administering global clusters from the command line
- About global querying in a global cluster setup
- Administering clusters in global cluster setup
- Setting up replicated data clusters
- Setting up campus clusters
- Connecting clusters–Creating global clusters
- Section VII. Troubleshooting and performance
- VCS performance considerations
- How cluster components affect performance
- How cluster operations affect performance
- VCS performance consideration when a system panics
- About scheduling class and priority configuration
- VCS agent statistics
- About VCS tunable parameters
- 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 issues with systemd unit service files
- Troubleshooting service groups
- Troubleshooting resources
- Troubleshooting sites
- Troubleshooting I/O fencing
- Fencing startup reports preexisting split-brain
- Troubleshooting CP server
- Troubleshooting server-based fencing on the VCS cluster nodes
- Issues during online migration of coordination points
- Troubleshooting notification
- Troubleshooting and recovery for global clusters
- Troubleshooting licensing
- Licensing error messages
- Troubleshooting secure configurations
- Troubleshooting wizard-based configuration issues
- Troubleshooting issues with the Veritas High Availability view
- VCS message logging
- VCS performance considerations
- Section VIII. Appendixes
Replacing I/O fencing coordinator disks when the cluster is online
Review the procedures to add, remove, or replace one or more coordinator disks in a cluster that is operational.
Warning:
The cluster might panic if any node leaves the cluster membership before the vxfenswap script replaces the set of coordinator disks.
To replace a disk in a coordinator disk group when the cluster is online
- Make sure system-to-system communication is functioning properly.
- Determine the value of the FaultTolerance attribute.
# hares -display coordpoint -attribute FaultTolerance -localclus
- Estimate the number of coordination points you plan to use as part of the fencing configuration.
- Set the value of the FaultTolerance attribute to 0.
Note:
It is necessary to set the value to 0 because later in the procedure you need to reset the value of this attribute to a value that is lower than the number of coordination points. This ensures that the Coordpoint Agent does not fault.
- Check the existing value of the LevelTwoMonitorFreq attribute.
#hares -display coordpoint -attribute LevelTwoMonitorFreq -localclus
Note:
Make a note of the attribute value before you proceed to the next step. After migration, when you re-enable the attribute you want to set it to the same value.
You can also run the hares -display coordpoint to find out whether the LevelTwoMonitorFreq value is set.
- Disable level two monitoring of CoordPoint agent.
# hares -modify coordpoint LevelTwoMonitorFreq 0
- Make sure that the cluster is online.
# vxfenadm -d
I/O Fencing Cluster Information: ================================ Fencing Protocol Version: 201 Fencing Mode: SCSI3 Fencing SCSI3 Disk Policy: dmp Cluster Members: * 0 (sys1) 1 (sys2) RFSM State Information: node 0 in state 8 (running) node 1 in state 8 (running)
- Import the coordinator disk group.
The file
/etc/vxfendg
includes the name of the disk group (typically, vxfencoorddg) that contains the coordinator disks, so use the command:# vxdg -tfC import 'cat /etc/vxfendg'
where:
-t specifies that the disk group is imported only until the node restarts.
-f specifies that the import is to be done forcibly, which is necessary if one or more disks is not accessible.
-C specifies that any import locks are removed.
- If your setup uses
VRTSvxvm
version, then skip to step 10. You need not set coordinator=off to add or remove disks. For other VxVM versions, perform this step:Where
version
is the specific release version.Turn off the coordinator attribute value for the coordinator disk group.
# vxdg -g vxfencoorddg set coordinator=off
- To remove disks from the coordinator disk group, use the VxVM disk administrator utility vxdiskadm.
- See the Cluster Server Installation Guide for detailed instructions.
Perform the following steps to add new disks to the coordinator disk group:
Add new disks to the node.
Initialize the new disks as VxVM disks.
Check the disks for I/O fencing compliance.
Add the new disks to the coordinator disk group and set the coordinator attribute value as "on" for the coordinator disk group.
Note that though the disk group content changes, the I/O fencing remains in the same state.
- From one node, start the vxfenswap utility. You must specify the disk group to the utility.
The utility performs the following tasks:
Backs up the existing
/etc/vxfentab
file.Creates a test file
/etc/vxfentab.test
for the disk group that is modified on each node.Reads the disk group you specified in the vxfenswap command and adds the disk group to the
/etc/vxfentab.test
file on each node.Verifies that the serial number of the new disks are identical on all the nodes. The script terminates if the check fails.
Verifies that the new disks can support I/O fencing on each node.
- If the disk verification passes, the utility reports success and asks if you want to commit the new set of coordinator disks.
Confirm whether you want to clear the keys on the coordination points and proceed with the vxfenswap operation.
Do you want to clear the keys on the coordination points and proceed with the vxfenswap operation? [y/n] (default: n) y
- Review the message that the utility displays and confirm that you want to commit the new set of coordinator disks. Else skip to step 16.
Do you wish to commit this change? [y/n] (default: n) y
If the utility successfully commits, the utility moves the
/etc/vxfentab.test
file to the/etc/vxfentab
file. - If you do not want to commit the new set of coordinator disks, answer n.
The vxfenswap utility rolls back the disk replacement operation.
- If coordinator flag was set to off in step 9, then set it on.
# vxdg -g vxfencoorddg set coordinator=on
- Deport the diskgroup.
# vxdg deport vxfencoorddg
- Re-enable the LevelTwoMonitorFreq attribute of the CoordPoint agent.You may want to use the value that was set before disabling the attribute.
# hares -modify coordpoint LevelTwoMonitorFreq Frequencyvalue
where Frequencyvalue is the value of the attribute.
- Set the FaultTolerance attribute to a value that is lower than 50% of the total number of coordination points.
For example, if there are four (4) coordination points in your configuration, then the attribute value must be lower than two (2).If you set it to a higher value than two (2) the CoordPoint agent faults.