A parallel service group runs simultaneously on more than one system in the cluster. Hybrid Service Groups. A hybrid service group is for replicated data clusters and is a combination of the two groups cited above. It behaves as a failover group within a system zone and a parallel group across system zones. It cannot fail over across system zones, and a switch operation on a hybrid group is allowed only if both systems are within the same system zone.
The ClusterService Group. The Cluster Service group is a special purpose service group, which contains resources required by VCS components. The group comes online on the first node that goes in the running state. A system has one agent per resource type that monitors all resources of that type; for example, a single IP agent manages all IP resources. When the agent is started, it obtains the necessary configuration information from VCS.
It then periodically monitors the resources, and updates VCS with the resource status. VCS agents are multithreaded, meaning a single VCS agent monitors multiple resources of the same resource type on one host. VCS monitors resources when they are online and offline to ensure they are not started on systems on which they are not supposed to run. For this reason, VCS starts the agent for any resource configured to run on a system when the cluster is started.
If no resources of a particular type are configured, the agent is not started. Agent Operation:. Monitor—Tests the status of a resource to determine if the resource is online or offline. Action—Performs actions that can be completed in a short time typically, a few seconds , and which are outside the scope of traditional activities such as online and offline. Info—Retrieves specific information for an online resource. Multiple Systems. VCS runs in a replicated state on each system in the cluster.
A private network enables the systems to share identical state information about all resources and to recognize which systems are active, which are joining or leaving the cluster, and which have failed. The private network requires two communication channels to guard against network partitions. For the VCS private network, two types of channels are available for heartbeating: network connections and heartbeat regions on shared disks.
The shared disk region heartbeat channel is used for heartbeating only, not for transmitting information as are network channels. Each cluster configuration requires at least two channels between systems, one of which must be a network connection. The remaining channels may be a combination of network connections and heartbeat regions on shared disks.
This requirement for two channels protects your cluster against network partitioning. If one of the network connections fails, two channels remain. If both network connections fail, the condition is in jeopardy, but connectivity remains via the heartbeat disk. Shared Storage. Shared storage provides multiple systems an access path to the same data, and enables VCS to restart applications on alternate systems when a system fails. Cluster Control, Communications, and Membership. It is responsible for building the running cluster configuration from the configuration files, distributing the information when new nodes join the cluster, responding to operator input, and taking corrective action when something fails.
It is typically known as the VCS engine. The engine uses agents to monitor and manage resources. Information about resource states is collected from the agents on the local system and forwarded to all cluster members.
This means HAD running on each node has a completely synchronized view of the resource status on each node. VCS uses private network communications between cluster nodes for cluster maintenance. The Low Latency Transport functions as a high-performance, low-latency replacement for the IP stack, and is used for all cluster communications. Traffic Distribution. LLT distributes load balances internode communication across all available private network links. This distribution means that all cluster communications are evenly distributed across all private network links maximum eight for performance and fault resilience.
If a link fails, traffic is redirected to the remaining links. LLT is responsible for sending and receiving heartbeat traffic over network links. Cluster Membership. GAB maintains cluster membership by receiving input on the status of the heartbeat from each node via LLT. When a system no longer receives heartbeats from a peer, it marks the peer as DOWN and excludes the peer from the cluster. Cluster Communications. GAB provides guaranteed delivery of point-to-point and broadcast messages to all nodes.
Cluster Topologies. An application runs on a primary, or master, server. A dedicated redundant server is present to take over on any failure. The redundant server is not configured to perform any other functions. This configuration is the simplest and most reliable.
The redundant server is on stand-by with full performance capability. In a symmetric configuration, each server is configured to run a specific application or service and provide redundancy for its peer.
An N-to-1 configuration is based on the concept that multiple, simultaneous server failures are unlikely; therefore, a single redundant server can protect multiple active servers. With the capabilities introduced by storage area networks SANs , you can not only create larger clusters, but more importantly, can connect multiple servers to the same storage.
N-to-N Configuration. An N-to-N configuration refers to multiple service groups running on multiple servers, with each service group capable of being failed over to different servers in the cluster. Storage Configurations. Basic Shared Storage Cluster. In this configuration, a single cluster shares access to a storage device, typically over a SAN. Share Nothing Cluster:.
There is no storage disk. Replicated Data Cluster:. In a replicated data cluster there is no shared disk. Global Cluster. A global cluster links clusters at separate locations and enables wide-area failover and disaster recovery. Configuring VCS means conveying to the VCS engine the definitions of the cluster, service groups, resources, and resource dependencies. VCS uses two configuration files in a default configuration:. The main. Include Clauses. Include clauses incorporate additional configuration files into main.
Cluster Definition. This section of main. System Definition. Each system designated as part of the cluster is listed in this section of main. Service Group Definition. Service group definitions in main. Resource Definition. This section in main. Service Group Dependency Clause. Resource Dependency Clause. The systems are configured as:. In an NFS configuration, the resource dependencies must be configured to bring up the IP address last. The types definition performs two important functions.
VCS components are configured using attributes. Cluster operations are enabled or restricted depending on the permissions with which you log on to VCS.
Cluster Administrator. Users in this category are assigned full privileges, including making configuration read-write, creating and deleting groups, setting group dependencies, adding and deleting systems, and adding, modifying, and deleting users. Cluster Operator. Group Administrator. Users in this category can perform all service group operations on specific groups, such as bringing groups and resources online, taking them offline, and creating or deleting resources.
Group Operator. Users in this category can bring service groups and resources online and take them offline. Cluster Guest. Users in this category have read-only access, meaning they can view the configuration, but cannot change it. Cluster vcs. The following concepts apply to users executing commands from the command line:. Users logged on as root or administrator are granted privileges that exceed those of Cluster Administrator, such as the ability to start and stop a cluster.
User Privileges in Global Clusters. VCS enforces user privileges across clusters. A cross-cluster online or offline operation is permitted only if the user initiating the operation has one of the following privileges:. Group Administrator or Group Operator privileges for the group on the remote cluster.
Cluster Administrator or Cluster Operator privileges on the remote cluster. A cross-cluster switch operation is permitted only if the user initiating the operation has the following privileges:. Group Administrator or Group Operator privileges for the group on both clusters. Cluster Administrator or Cluster Operator privileges on both clusters. System States. The following table provides a list of VCS system states and their descriptions. The running configuration was lost. A system transitions into this state for the following reasons:.
The system has joined the cluster and its configuration file is valid. The system is leaving the cluster. The system has left the cluster. A hastop -force command has forced the system to leave the cluster. The system has left the cluster unexpectedly.
The system has joined the cluster. The system is leaving the cluster gracefully. The system is building the running configuration from the disk configuration. The system has joined the cluster with a stale configuration file. The system has not joined the cluster because it does not have a system entry in the configuration. Its very useful.
All in one go. Could you please let me know how to find which node is currently holding the vcs membership.
Show the attributes in the default list. This adds these attributes to the default list of attributes that is shown in the resources views. This removes the listed attributes from the default list of attributes that is shown in the resources views. Forces the heartbeat link status view to only show information relating to the particular system that the plugin is running on. If the Veritas Cluster Server has authentication enabled on the host, the Veritas Cluster Server plug-in may fail if the netprobe is being run by a non-root user.
To enable the VCS plug-in to work in such a scenario, use the halogin command on the host to save the authentication information. With this command, the encrypted information a. The information is stored until the user ends the session. Note: The lltconfig and gabconfig commands are not covered by this approach and these commands will need root permissions to run.
Select version Geneos v4. Information is extracted by running a number of Veritas executables and parsing their output. Gen The generation number indicating a startup time. Mandatory: Yes. Mandatory: No. Valid domain types are:.
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