Configuring an active-passive IBM Spectrum Scale deployment

You can deploy a IBM Spectrum Scale Primary instance and attach a deployed IBM Spectrum Scale Passive instance to create a configuration suitable for disaster recovery.

About this task

Active-passive is a disaster recovery (DR) configuration setup between racks that are located at larger distances. The Primary instance is on one rack while the Passive instance is on the other rack. The two racks need to be set up for Disaster Recovery and be able to set up replication at the volume level. In an active-passive configuration, the replication is done at the volume level. This configuration is different than the active-active configuration where replication is managed by IBM Spectrum Scale, by using an active Mirror replica. For this reason, a Primary instance cannot be part of both an active-active and an active-passive configurations at the same time. The Primary instance can be either part of an active-active configuration (and use IBM Spectrum Scale synchronous replication, with an active Mirror replica) or be part of an active-passive replication, and use volume replication, with a IBM Spectrum Scale Passive side ready for takeover.

The following procedure shows the general steps you can take to configure an active / passive deployment for disaster recovery situations. In this configuration, a IBM Spectrum Scale Primary instance is deployed to one rack (which is referred to as the Primary rack), while a IBM Spectrum Scale Passive instance is deployed on a separate rack (referred to as the Passive rack), usually at a separate location. Both systems must be configured for disaster recovery.

Procedure

  1. On the Primary rack, create appropriate volumes as needed.
  2. On the Passive rack, create identical (in number and size) volumes as on the Primary rack.
    Note: You can use existing volumes when you deploy the primary or passive configurations, but be aware that any data that is contained in these volumes is lost because IBM Spectrum Scale reformats the volumes.
  3. Configure block storage replication between each pair of identical volumes on the Primary and Passive racks. Configure block storage replication on the Primary rack, and then accept the replication request for each volume pair on the Passive rack.
  4. Deploy a IBM Spectrum Scale Passive instance on the Passive rack, and attach the replicated volumes.
    Ensure that the following requirements are met:
    • This Passive instance has the same number of IBM Spectrum Scale nodes as the Primary configuration to which it will be attached.
    • The same number of volumes, with the same sizes, are used in both the Passive and Primary deployments for the specified file system.
    • The file system name on the Passive deployment must be the same as the file system name on the Primary deployment.
    • The cluster name for the Passive deployment must be different from the cluster name used by the Primary deployment.

    Wait for the virtual machines to be allocated and note the IP address of its GPFS_Manager node.

  5. Wait for the virtual application to finish launching. When the processing completes, a status of Running is displayed.
  6. Deploy a IBM Spectrum Scale Primary instance on the Primary rack.
    As you deploy your Primary instance, you have the option to configure and attach the Passive instance during deployment, or you can deploy the Primary instance by itself now, and attach the Passive instance at a later time.
    • If you choose to configure and attach the deployed Passive instance during this Primary deployment, complete the following steps:
      1. On the deployment configuration dialog, ensure that the check box for Active Configuration is cleared and that the check box for Passive Configuration is selected.
      2. Expand the Passive Configuration section and supply the IP address for the GPFS_Manager node for the Passive instance.

    Otherwise, if you choose to deploy the Primary instance by itself for now and plan to attach the deployed Passive instance to the Primary instance at a later time, ensure that the check boxes for Active Configuration and Passive Configuration are both cleared.

  7. Proceed to the Placement dialog and attach appropriate volumes.
  8. Launch the deployment process.
    When the processing completes, a status of Running is displayed.
  9. If you deployed the Primary instance by itself, then from the Primary system run the Add New Member operation and specify the IP address of the GPFS_Manager node for the Passive instance to attach it to the Primary instance.

Results

This procedure attaches the Passive configuration to the Primary configuration, creating the active/passive environment.

What to do next

If you have not already done so, you can deploy an instance of the IBM® shared service for IBM Spectrum Scale and configure it to use your new cluster.As an alternative to using the IBM Spectrum Scale shared service, starting with IBM Spectrum Scale pattern V1.2.5.0, the clients can directly provide the IBM Spectrum Scale server connection information at deployment time.

Deploy other workload patterns that contain the IBM Spectrum Scale Client Policy (or alternatively, the IBM Spectrum Scale Client script packages). These workloads can then access the volumes made available by your IBM Spectrum Scale cluster.

When failover situations occur, you can perform the following general tasks:
  • If this is a planned failover and the Primary rack is still active, run the Prepare Primary for Takeover cluster operation on the Primary rack. This operation detaches the replicated volumes from the Primary rack and prepares for breaking the replication.
  • If the Primary rack is still up, perform failover on the Primary rack, on the replicated volumes.
  • If the Primary rack is down, run Failover from the Passive rack, on the replicated volumes. This operation breaks the replication.
  • On the Passive rack, run the Passive Takeover cluster operation. This operation cause the Passive instance to become a new Primary configuration.
  • If the original Primary instance is still available, you can attach it as a new Passive instance. On the new Primary rack, run the Add New Member operation, select the Passive configuration type, and enter the Manager IP address for the original Primary rack, causing it to perform as a new Passive replica for the new Primary instance.
  • If you have a IBM Spectrum Scale shared service instance that is connecting to the old Primary cluster, you need to delete and redeploy an instance of the IBM shared service for IBM Spectrum Scale and configure it to use the new Primary cluster.
  • You will need to run the Connect to Server operation on each IBM Spectrum Scale client to access the file system.