Forum Discussion

paragarw's avatar
paragarw
Level 4
10 years ago

Is it possible to have a Critical and Non-Critical application resource in the same service group

I have a requirement where I have two application resources(rs-app-db-004  and rs-app-rm-004). in the same service group but I want to make one as Non-Critical. Please be noted that both the applications share the same mount point.

My requirement is that if the Non-Critical application( rs-app-db-004) goes down, then the service group should be be partially Online and no failover should take place. The critical application should continue to function And if the Critical application(rs-app-rm-004) goes down then irrespective whether  Non-Critical application is faulted or Onilne, the whole service group should failover to  the other node. Currently both the applictaions are Critical.

Do i also need to make Non-critical resource dependent on the the Critical application? I am not sure on this as theoritically failure of critical application should failover the whole service group.

Also I want to understand is making this resource rs-app-db-004 non critical would have any implications or not during failover or elsewhere? If yes then request you to  update me on that.

Is this supported in my current version? if not then is there any patch to address this

  • The version of VERITAS  installed is  5.1SP1

I read one of the link that doing so can have implication.

http://www.symantec.com/business/support/index?page=content&id=TECH198473&profileURL=https%3A%2F%2Fsymaccount-profile.symantec.com%2FSSO%2Findex.jsp%3FssoID%3D1427713514227L157f501L0qCms00A96GeFtbRX3WW4e5XTcSB

 

The dependency of the resources in the service group is shown below.

 hares -dep
#Group           Parent                  Child
ClusterService   webip                   csgnic
SG-APP-DS_RM-004 rs-app-db-004           rs-mnt-rmdb-004
SG-APP-DS_RM-004 rs-app-db-004           rs-ip-dsarmvp-cls-004
SG-APP-DS_RM-004 rs-app-rm-004           rs-mnt-rmdb-004
SG-APP-DS_RM-004 rs-app-rm-004           rs-ip-dsarmvp-cls-004
SG-APP-DS_RM-004 rs-ip-dsarmvp-cls-004   rs-proxynic-rmdb-004
SG-APP-DS_RM-004 rs-mnt-rmdb-004         rs-vol-dsappvol-004
SG-APP-DS_RM-004 rs-vol-dsappvol-004     rs-dg-dsappdg-004

 

 

business continuity
Cluster Server
Linux
  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    10 years ago

    Hi,

     

    Just make sure to have the non-critical resource on top of, or on the same level as the critical resource then you should not face the issue described in the note.

     

    About critical and non-critical resources

    The Critical attribute for a resource defines whether a service group fails over when the resource faults. If a resource is configured as non-critical (by setting the Critical attribute to 0) and no resources depending on the failed resource are critical, the service group will not fail over. VCS takes the failed resource offline and updates the group status to online|partial. The attribute also determines whether a service group tries to come online on another node if, during the group's online process, a resource fails to come online.

  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    Level 6
    10 years ago

    Hi,

     

    Just make sure to have the non-critical resource on top of, or on the same level as the critical resource then you should not face the issue described in the note.

     

    About critical and non-critical resources

    The Critical attribute for a resource defines whether a service group fails over when the resource faults. If a resource is configured as non-critical (by setting the Critical attribute to 0) and no resources depending on the failed resource are critical, the service group will not fail over. VCS takes the failed resource offline and updates the group status to online|partial. The attribute also determines whether a service group tries to come online on another node if, during the group's online process, a resource fails to come online.

  • paragarw's avatar
    paragarw
    Level 4
    10 years ago

    Hi Riaan,

    Thanks for your feedback. I read the below link and hence had doubts.

    http://www.symantec.com/business/support/index?page=content&id=TECH198473&profileURL=https%3A%2F%2Fsymaccount-profile.symantec.com%2FSSO%2Findex.jsp%3FssoID%3D1427713514227L157f501L0qCms00A96GeFtbRX3WW4e5XTcSB

    And as per this,

     

    If a non-critical (Critical = 0) resource in a Veritas Cluster Server (VCS) service group is in FAULTED state when the service group is being brought online, the service group will remain indefinitely in "STARTING|PARTIAL" state.

    Once the service group enters this state, users will not be able to switch over the service group to another node, as the group is in a transitional state; further attempts to take the service group offline may result in some resources stuck in W_OFFLINE_REVERSE or W_OFFLINE_PROPAGATE state.

     

    Cause

    If online propagation reaches a non-critical resource in FAULTED state, it will prevent further propagation but will not trigger a service group fault. Consequently, the service group will neither succeed nor fail to become online, thus remaining indefinitely in STARTING|PARTIAL state.

    This is an expected behavior (as per the design) of VCS engine prior to version 6.0, but can potentially result in unnecessary interruptions depending on the configuration, especially if the user is unaware of the exact cause.

  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    Level 6
    10 years ago

    Yes, i know what is in the note. But it applies to lower level (NON CRITICAL) resources with upper level (CRITICAL) resources that depend on the lower level ones.

    Hence I said if the resources are on top level you'll be fine.