VCS Brief Notes. Veritas Cluster Service.

                                         VERITAS CLUSTER

-              Cluster is a combination of multiple nodes connected inside a network to provide high availability to the application at any point of time.

-              There are two types of configurations asymmetric and symmetric.

-              symmetric configuration is also known as active passive configuration at any point of time one node will be active and another node will be passive.

-              n symmetric configuration both nodes are active, each performing its own task if one node fails the other will take the responsibility for running all the services.

-              e Service groups inside cluster perform 1)fail over 2) parallel 3) hybrid operations,

-              e two daemons in a cluster are:

1)HAD daemon and 2)HA shadow daemon, these two daemons are always running in all the nodes of a cluster.

-              he entire configuration of the cluster is managed by HAD daemon HA shadow acts like backup and also perform load balance.

-              There are two main configuration files inside cluster

Main.cf:- which maintains the cluster id the list of users can manage cluster and the no of service groups created inside the cluster.

Types.cf:- this file maintains default attributes information

-              The primary task of HAD daemon is to maintain same copy of these files inside the cluster it also maintain backup of these file before performing any modifications to the cluster.

-              The communication between the cluster is done with the help of high priority links used for private communication, it uses LLT (low latency transfer protocol)and GAB(group membership atomic broadcast protocol) protocols to communication b/w the nodes.

-              These files are responsible in maintaining the communication information inside the node.

/etc/llthosts:- contains node ID and node name.

/etc/llttab:- contains cluster ID, node id and the no.of links used for communication b/w the nodes.

/etc/gabtab:- maintains the membership information of nodes inside the cluster.

Installation requirements for cluster:-

Min 512mb ram,NIC cards for private public communication and common storage

Appilication Requirements to install on a cluster:-

1)It should have independent stop start procedures

2)It should have ability to clear falls and individual monitoring service

3) must have capable of running on multiple nodes should support common storage

*hastatus –sum            –status of a cluster

*hagrp –list                    -list service groups

Start and stop daemons

cd /etc/rc3.d    - use to start and stop daemons

#hastatrt

#hastop   -is use to stop our local node

#hastop –all

How to stop the remote node

#hastop –sys sys1 –evacuate

Taking a snapshot of vcs configuration files:--

#hasnap –backup –m “test backup of nfssg”

Managing users inside vcs:-

#hauser –list   (will list users of vcs)

#hauser –display (will display users along vth priviliges)

#hauser –add user1 (crate a user)

#hauser –addpriv user1  Administrator (to assign a priviliges to uer)

#hauser –delpriv user1 Administrator  (to remove priviliges)

#hagrp –list

#hagrp –state  -to know the status of service group

#hagrp –resources nfssg

Quering resources types:-

#hatype  –resources ip

#hatype  –list

#haclus  –list

#haclus  –display

#haclus  -state