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
VCS behavior when an online resource faults
In the following example, a resource in an online state is reported as being offline without being commanded by the agent to go offline.
VCS goes through the following steps when an online resource faults:
VCS first verifies the Monitor routine completes successfully in the required time. If it does, VCS examines the exit code returned by the Monitor routine. If the Monitor routine does not complete in the required time, VCS looks at the FaultOnMonitorTimeouts (FOMT) attribute.
If FOMT=0, the resource will not fault when the Monitor routine times out. VCS considers the resource online and monitors the resource periodically, depending on the monitor interval.
If FOMT=1 or more, VCS compares the CurrentMonitorTimeoutCount (CMTC) with the FOMT value. If the monitor timeout count is not used up, CMTC is incremented and VCS monitors the resource in the next cycle.
If FOMT= CMTC, this means that the available monitor timeout count is exhausted and VCS must now take corrective action. VCS checks the Frozen attribute for the service group. If the service group is frozen, VCS declares the resource faulted and calls the resfault trigger. No further action is taken.
If the service group is not frozen, VCS checks the ManageFaults attribute at the resource level. VCS marks the resource as ONLINE|ADMIN_WAIT and fires the resadminwait trigger if its group-level value is NONE or if its resource-level value is IGNORE. If ManageFaults is set to ACT at the resource level or ALL at the group level, VCS invokes the Clean function with the reason Monitor Hung.
Note:
The resource-level ManageFaults value supersedes the corresponding service group-level value. VCS honors the service group-level ManageFaults value only when the corresponding resource-level value is blank ("").
If the Clean function is successful (that is, Clean exit code = 0), VCS examines the value of the RestartLimit attribute. If Clean fails (exit code = 1), the resource remains online with the state UNABLE TO OFFLINE. VCS fires the resnotoff trigger and monitors the resource again.
If the Monitor routine does not time out, it returns the status of the resource as being online or offline.
If the ToleranceLimit (TL) attribute is set to a non-zero value, the Monitor cycle returns offline (exit code = 100) for a number of times specified by the ToleranceLimit and increments the ToleranceCount (TC). When the ToleranceCount equals the ToleranceLimit (TC = TL), the agent declares the resource as faulted.
If the Monitor routine returns online (exit code = 110) during a monitor cycle, the agent takes no further action. The ToleranceCount attribute is reset to 0 when the resource is online for a period of time specified by the ConfInterval attribute.
If the resource is detected as being offline a number of times specified by the ToleranceLimit before the ToleranceCount is reset (TC = TL), the resource is considered faulted.
After the agent determines the resource is not online, VCS checks the Frozen attribute for the service group. If the service group is frozen, VCS declares the resource faulted and calls the resfault trigger. No further action is taken.
If the service group is not frozen, VCS checks the ManageFaults attribute. If ManageFaults=NONE, VCS marks the resource state as ONLINE|ADMIN_WAIT and calls the resadminwait trigger. If ManageFaults=ALL, VCS calls the Clean function with the CleanReason set to Unexpected Offline.
If the Clean function fails (exit code = 1) the resource remains online with the state UNABLE TO OFFLINE. VCS fires the resnotoff trigger and monitors the resource again. The resource enters a cycle of alternating Monitor and Clean functions until the Clean function succeeds or a user intervenes.
If the Clean function is successful, VCS examines the value of the RestartLimit (RL) attribute. If the attribute is set to a non-zero value, VCS increments the RestartCount (RC) attribute and invokes the Online function. This continues till the value of the RestartLimit equals that of the RestartCount. At this point, VCS attempts to monitor the resource.
If the Monitor returns an online status, VCS considers the resource online and resumes periodic monitoring. If the monitor returns an offline status, the resource is faulted and VCS takes actions based on the service group configuration.