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Sunday, November 10, 2013

Migrating disks within coordinator disk group from one array to another.

Last week I was working on storage migration tasks in which I envisioned to migrate disks within coordinator disk group from old array to newly deployed array.

To me, it was first time doing this task so I decided to note down the steps and after successfully completing the task decided to share with my all friends out there!

There can be several methods to do this task however for me below steps worked very well but if anyone has any better set of instructions doing this then request to share those.

Let's start then -

1. If VCS is running, shut it down locally:

# hastop -all -force

2. Stop I/O fencing on all nodes. This removes any registration keys on the disks.

# /etc/init.d/vxfen stop   (on all 3 cluster nodes)

3. Import the coordinator disk group. The file /etc/vxfendg includes the name of the disk group (for example, vxfencoorddg) that contains the coordinator disks, so use the command -

# vxdg -tfC import 'cat /etc/vxfendg'
# vxdg -tfC import vxfencoorddg


-t specifies that the disk group is imported only until the system restarts.
-f specifies that the import is to be done forcibly, which is necessary if one or more disks is not accessible.
-C specifies that any import blocks are removed.

4. Turn off the coordinator attribute value for the coordinator disk group.

# vxdg -g vxfencoorddg set coordinator=off

5. Remove old disks and add new disks

    First remove N-1 disks from fence disk group
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg01
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg02
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg03
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg04
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg05
       # vxdg -g vxfencoorddg rmdisk vxfencoorddg06

        Add disk for fence disk group

       # vxdisk list | egrep 'apevmx13_139|apevmx13_140|apevmx13_143|apevmx13_145|apevmx14_139|apevmx14_140|apevmx14_141'
    apevmx13_139 auto:cdsdisk    -            -            online
    apevmx13_140 auto:cdsdisk    -            -            online
    apevmx13_143 auto:cdsdisk    -            -            online
    apevmx13_145 auto:cdsdisk    -            -            online
    apevmx14_139 auto:cdsdisk    -            -            online
    apevmx14_140 auto:cdsdisk    -            -            online
    apevmx14_141 auto:cdsdisk    -            -            online

    # vxdg -g vxfencoorddg adddisk vxfencoorddg01=apevmx13_139
    # vxdg -g vxfencoorddg adddisk vxfencoorddg02=apevmx13_140
    # vxdg -g vxfencoorddg adddisk vxfencoorddg03=apevmx13_143
    # vxdg -g vxfencoorddg adddisk vxfencoorddg04=apevmx13_145
    # vxdg -g vxfencoorddg adddisk vxfencoorddg05=apevmx14_139
    # vxdg -g vxfencoorddg adddisk vxfencoorddg06=apevmx14_140

    Remove the remaining one disk from enclosure apedmx06

    # vxdg -g vxfencoorddg rmdisk vxfencoorddg07

    Add the 7th disk from enclosure apevmx14

    # vxdg -g vxfencoorddg adddisk vxfencoorddg07=apevmx14_141

6. Set the coordinator attribute value as "on" for the coordinator disk group.

# vxdg -g vxfencoorddg set coordinator=on

7. Run disk scan on all nodes

# vxdisk scandisks   (Run on all cluster nodes)

8. Check if fencing disks are visible on all nodes

# vxdisk -o alldgs list | grep fen

9. After replacing disks in a coordinator disk group, deport the disk group:

# vxdg deport 'cat /etc/vxfendg'
# vxdg deport vxfencoorddg

10. Verify if the fencing diskgroup is deported

# vxdisk -o alldgs list | grep fen

11. On each node in the cluster, start the I/O fencing driver:

# /etc/init.d/vxfen start  (on all 3 cluster nodes)

12. hastart on all cluster nodes. 

# hastart  (on all 3 cluster nodes)

That's it, these 12 steps takes you through migrating disks within coordinator disk group from one array to another.

HTH someone!