Forum Discussion

Rajan_Iyer's avatar
Rajan_Iyer
Level 4
13 years ago

Difference Between CVM Nid & CM Nid

Hi,

In my set up of 4 Node CFS Parallet Cluser I have below queries. My scenario has been given as below.

/etc/vx/bin/vxclustadm nidmap

Name                  CVM Nid  CM Nid       State
node1                      2          0          Joined: Master
node2                      3          1          Joined: Slave
node3                      1          2          Joined: Slave
node4                      0          3          Joined: Slave
 

fsclustadm -v showprimary [Mount Point]
node1

Also I have below queries on the same.

1. What is the difference between CVM & CM Nid.

2. In case of Creating shared Disk Group or Expanding group do I need to perform all operations on node1 as it is Master node.

3. In case of scheduled maintenance of node1 do I need to change the the role of Master role by "fsclustadm -v setprimary /mount_point" to another node manually else it will take care by its own.

4. Also please share brief steps of Creating Disk Group and Mounting in case of CFS Parallell access.

5. Also is there any CFS configuration file which consist of Details of Master/Slave Role.

 

 

Thanks

Rajan

 

 

 

 

 

business continuity
Cluster Server
  • Gaurav_S's avatar
    Gaurav_S
    13 years ago

    Hi Rajan,

    Find your answers below

    1. What is the difference between CVM & CM Nid.

    - CVM Node ID is the order in which CVM recognizes the nodes & CM (cluster managed) node ID is cluster node IDs which would map from /etc/llthosts file.

    2. In case of Creating shared Disk Group or Expanding group do I need to perform all operations on node1 as it is Master node.

    -- Yes, in a CVM cluster, you can perform most of vxvm level operations from Master node only. If you try to run any configuration change command from secondary, it will error..

    3. In case of scheduled maintenance of node1 do I need to change the the role of Master role by "fsclustadm -v setprimary /mount_point" to another node manually else it will take care by its own.

    -- That will be taken care by cluster itself .... if you shutdown the primary node for any filesystem, the secondary will be promoted to primary & new primary will manage the metadeta of filesystem. Just FYI, primary of a filesystem can different & CVM primary can be different. For different CFS filesystems, you can have any node as primary (not necessarily CVM master). In case of CVM master, if you shutdown the CVM primary, the role will be shifted to any available secondary.

    4. Also please share brief steps of Creating Disk Group and Mounting in case of CFS Parallell access.

    --Have a look at CVM admin guide ...

    https://sort.symantec.com/documents

    An example of solaris 5.1 can be found here:

    https://sort.symantec.com/public/documents/sfha/5.1sp1/solaris/productguides/html/sfcfs_admin/ch03s02.htm

     

    5. Also is there any CFS configuration file which consist of Details of Master/Slave Role.

    --Thats a nice question, to my knowledge, answer is No. This is maintained at kernel level. As soon you online the CVM service group in cluster, first node which starts CVM takes the master role.You need to directly query the vxconfigd daemon to know the master node.

    # vxdctl -c mode.

     

    Hope this helps

     

    Gaurav

  • Gaurav_S's avatar
    Gaurav_S
    Moderator
    13 years ago

    Hi Rajan,

    Find your answers below

    1. What is the difference between CVM & CM Nid.

    - CVM Node ID is the order in which CVM recognizes the nodes & CM (cluster managed) node ID is cluster node IDs which would map from /etc/llthosts file.

    2. In case of Creating shared Disk Group or Expanding group do I need to perform all operations on node1 as it is Master node.

    -- Yes, in a CVM cluster, you can perform most of vxvm level operations from Master node only. If you try to run any configuration change command from secondary, it will error..

    3. In case of scheduled maintenance of node1 do I need to change the the role of Master role by "fsclustadm -v setprimary /mount_point" to another node manually else it will take care by its own.

    -- That will be taken care by cluster itself .... if you shutdown the primary node for any filesystem, the secondary will be promoted to primary & new primary will manage the metadeta of filesystem. Just FYI, primary of a filesystem can different & CVM primary can be different. For different CFS filesystems, you can have any node as primary (not necessarily CVM master). In case of CVM master, if you shutdown the CVM primary, the role will be shifted to any available secondary.

    4. Also please share brief steps of Creating Disk Group and Mounting in case of CFS Parallell access.

    --Have a look at CVM admin guide ...

    https://sort.symantec.com/documents

    An example of solaris 5.1 can be found here:

    https://sort.symantec.com/public/documents/sfha/5.1sp1/solaris/productguides/html/sfcfs_admin/ch03s02.htm

     

    5. Also is there any CFS configuration file which consist of Details of Master/Slave Role.

    --Thats a nice question, to my knowledge, answer is No. This is maintained at kernel level. As soon you online the CVM service group in cluster, first node which starts CVM takes the master role.You need to directly query the vxconfigd daemon to know the master node.

    # vxdctl -c mode.

     

    Hope this helps

     

    Gaurav

  • Rajan_Iyer's avatar
    Rajan_Iyer
    Level 4
    13 years ago

    Hi Gaurav,

     

    Thanks a lot for all detailed answers which has really cleared my doubts a lot.

     

    Thanks

    Rajan

  • Rajan_Iyer's avatar
    Rajan_Iyer
    Level 4
    13 years ago

    Hi Gaurav,

    I would like to jus clarify my final doubt.

    In case of VxVM configurations all operation need to be managed from CFS Master not CVM Master. [Considering both Masters are different]

    Also clarify what operations need to be performed from CVM Master & CFS Master.

     

    Thanks

    Rajan

     

     

     

  • Gaurav_S's avatar
    Gaurav_S
    Moderator
    13 years ago

    Hi Rajan,

    All configurations pertaining to vxvm will be done from CVM Master (not CFS) ...

    Usually CFS Master related operations, you need not to touch stuff, it will mainly be managed by CFS itself.. major operations are like maintaining the metadeta... collaboration for locks etc..

     

    Gaurav