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
About resource monitoring
VCS agents poll the resources periodically based on the monitor interval (in seconds) value that is defined in the MonitorInterval or in the OfflineMonitorInterval resource type attributes. After each monitor interval, VCS invokes the monitor agent function for that resource. For example, for process offline monitoring, the process agent's monitor agent function corresponding to each process resource scans the process table in each monitor interval to check whether the process has come online. For process online monitoring, the monitor agent function queries the operating system for the status of the process id that it is monitoring. In case of the mount agent, the monitor agent function corresponding to each mount resource checks if the block device is mounted on the mount point or not. In order to determine this, the monitor function does operations such as mount table scans or runs statfs equivalents.
With intelligent monitoring framework (IMF), VCS supports intelligent resource monitoring in addition to poll-based monitoring. IMF is an extension to the VCS agent framework. You can enable or disable the intelligent monitoring functionality of the VCS agents that are IMF-aware. For a list of IMF-aware agents, see the Cluster Server Bundled Agents Reference Guide.
See How intelligent resource monitoring works.
See Enabling and disabling intelligent resource monitoring for agents manually.
See Enabling and disabling IMF for agents by using script.
Poll-based monitoring can consume a fairly large percentage of system resources such as CPU and memory on systems with a huge number of resources. This not only affects the performance of running applications, but also places a limit on how many resources an agent can monitor efficiently.
However, with IMF-based monitoring you can either eliminate poll-based monitoring completely or reduce its frequency. For example, for process offline and online monitoring, you can completely avoid the need for poll-based monitoring with IMF-based monitoring enabled for processes. Similarly for vxfs mounts, you can eliminate the poll-based monitoring with IMF monitoring enabled. Such reduction in monitor footprint will make more system resources available for other applications to consume.
Note:
Intelligent Monitoring Framework for mounts is supported only for the VxFS, ext4, and XFS file system types.
With IMF-enabled agents, VCS will be able to effectively monitor larger number of resources.
Thus, intelligent monitoring has the following benefits over poll-based monitoring:
Provides faster notification of resource state changes
Reduces VCS system utilization due to reduced monitor function footprint
Enables VCS to effectively monitor a large number of resources
Consider enabling IMF for an agent in the following cases:
You have a large number of process resources or mount resources under VCS control.
You have any of the agents that are IMF-aware.
For information about IMF-aware agents, see the following documentation:
See the Cluster Server Bundled Agents Reference Guide for details on whether your bundled agent is IMF-aware.
See the Storage Foundation Cluster File System High Availability Installation Guide for IMF-aware agents in CFS environments.