InfoScale™ 9.0 Cluster Server 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
- Configuring IPsec for encrypted communication over 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
- About application monitoring on single-node clusters
- 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
- 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. 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
- Configuring clusters for global cluster setup
- Configuring service groups for global cluster setup
- 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 VI. 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
- VCS message logging
- VCS performance considerations
- Section VII. Appendixes
Auto-revival of service group dependency trees upon recovery of faulted resources
Consider a configuration with the following service group and resource dependencies:
Service group SG3 contains three resources, R1, R2, and R3. R1 is dependent on R2, which in turn is dependent on R3 (R1 > R2 > R3).
SG2 is dependent on SG3 (SG2 > SG3).
SG1 is dependent on SG2 (SG1 > SG2).
In such a configuration, if R3 faults, VCS triggers a failover. It takes SG1, SG2, and SG3 offline and attempts to find a target node on which to bring the service groups online. If a suitable node is not found, SG3 remains in the OFFLINE|FAULTED state and SG1 and SG2 remain in the OFFLINE state.
Typically, leaf-level resources like R3 are infrastructure components - often persistent (OnOnly) resources (for example, NIC). Such a resource fault triggers a chain reaction and the entire dependency tree goes down. When that resource recovers automatically, without any VCS user intervention, only the state of the recovered resource changes to ONLINE. The dependent resources and its service group (R2, R1, and SG3) remain in the OFFLINE|FAULTED state and the parent service groups remain in the OFFLINE state.
From release 9.0.2 onwards, InfoScale provides the auto-revival feature for service group dependency trees. When this feature is enabled, and a faulted resource comes online, the dependent resources and service groups - whose states were directly affected by the fault, and not due to other conditions or events - are automatically brought online. For example, in this sample configuration (SG1 > SG2 > SG3 (R1 > R2 > R3)), VCS revives only those dependent resources and service groups that went into the OFFLINE|FAULTED or OFFLINE state specifically due to that resource (R3) fault.
The auto-revival of a service group dependency tree works only when the following prerequisites are met:
The cluster protocol version is 11100 or higher.
The cluster version is 9.0.2 or higher.
The dependencies between the service groups are set to any of the following:
online local hard
online local firm
online remote firm
online global firm
online site firm
Note:
The auto-revival feature is not supported with global service groups.