Setting the order of existing coordination points using the web-based installer
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Setting the order of existing coordination points using the web-based installer

This section describes the reasons, benefits, considerations, and the procedure to set the order of the existing coordination points using the web-based installer.

It does not apply to majority-based I/O fencing.

About deciding the order of existing coordination points

You can decide the order in which coordination points can participate in a race during a network partition. In a network partition scenario, I/O fencing attempts to contact coordination points for membership arbitration based on the order that is set in the vxfenmode file.

When I/O fencing is not able to connect to the first coordination point in the sequence it goes to the second coordination point and so on. To avoid a cluster panic, the surviving subcluster must win majority of the coordination points. So, the order must begin with the coordination point that has the best chance to win the race and must end with the coordination point that has the least chance to win the race

For fencing configurations that use a mix of coordination point servers and coordination disks, you can either specify coordination point servers before coordination point disks or disks before servers.

Note:

Disk-based fencing does not support setting the order of existing coordination points.

Considerations to decide the order of coordination points

  • Choose coordination points based on their chances gain membership on the cluster during the race and hence gain control over a network partition. In effect, you have the ability to save a partition.

  • First in the order must be the coordination point that has the best chance to win the race. The next coordination point you list in the order must have relatively lesser chance to win the race. Complete the order such that the last coordination point has the least chance to win the race.

Setting the order of existing coordination points using the web-based installer

To set the order of existing coordination points for server-based fencing using the web-based installer

  1. Start the web-based installer.

    See Starting the web-based installer.

  2. On the Select a task and a product page, select the task and the product as follows:

    Task

    I/O Fencing configuration

    Product

    Symantec Storage Foundation and High Availability

    Click Next.

  3. Verify the cluster information that the installer presents and confirm whether you want to configure I/O fencing on the cluster.
  4. On the Select Cluster page, enter the system name and click Yes.
  5. On the Select Cluster page, click Next if the installer completes the cluster verification successfully.

    The installer performs the initial system verification. It checks for the system communication. It also checks for release compatibility, installed product version, platform version, and performs product prechecks.

  6. The installer may prompt you to reconfigure fencing if it is already enabled. Click Yes to reconfigure fencing.

    Click Yes.

  7. On the Select Fencing Type page, select the Set the order of existing coordination points option.
  8. Confirm OK at the installer message about the procedure.
  9. Decide the new order by moving the existing coordination points to the box on the window in the order you want. If you want to change the current order of coordination points, click Reset and start again.
  10. Click Next if the information is correct.
  11. On the Confirmation window, click Yes.

    Installer prepares the vxfenmode file on all nodes and runs the vxfenswap utility to update the new order of coordination points.

  12. On the Completion page, view the summary file, log file, or response file to confirm the configuration.
  13. Select the check box to specify whether you want to send your installation information to Symantec.

    Click Finish.

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