IBM Storage Scale Server configurations

Several IBM Storage Scale Server configurations are supported, which you can easily scale to fit the needs of your environment.

IBM Storage Scale Primary configuration

A single deployment of a IBM Storage Scale Primary configuration can support 1, 3, 5, or 7 IBM Storage Scale Server nodes. At deployment time, the administrator chooses the scale of the IBM Storage Scale server cluster, and must ensure that there are enough compute nodes available to support the selected scale of the IBM Storage Scale cluster. This primary server can have a mirrored replica attached for improved quality of service.

IBM Storage Scale Mirrored configuration

A IBM Storage Scale Mirrored configuration, consisting of a IBM Storage Scale Mirror deployment and a IBM Storage Scale Tiebreaker deployment, is an active replica of the IBM Storage Scale Primary server deployment to which it is attached, and ensures a highly available file system for use by client applications. The IBM Storage Scale Tiebreaker decides which IBM Storage Scale configuration, Primary or Mirror, takes over the primary role of serving clients in the event that one or the other becomes unusable. The IBM Storage Scale Mirror deployment can also support 1,3,5, or 7 cluster members, and the configuration is constrained to match its mirrored, Primary configuration. You can deploy the IBM Storage Scale Mirror and IBM Storage Scale Tiebreaker configurations on any IBM® Cloud Pak System Software for Power® instances that have IP connectivity to the IBM Storage Scale Primary deployment, but you should avoid significant network latency, which might affect file system performance.

Important: As a best practice toward ensuring high availability, your Primary, Mirror, and Tiebreaker configurations should be located on separate systems in your environment, such that if any one IBM Storage Scale configuration becomes unavailable, the other two are unaffected and can continue to operate.

If you have three Cloud Pak System Software for Power instances in different data centers, or in different zones of a single data center, you should deploy these three IBM Storage Scale Server configurations each in a separate system.

If you have two Cloud Pak System Software for Power instances, you can install an external IBM Storage Scale Tiebreaker node on a separate system and attach that separate node to your IBM Storage Scale cluster. For more information about setting up this external Tiebreaker node, see the Related link.

As an additional option with only two Cloud Pak System Software for Power instances, instead of installing an external IBM Storage Scale Tiebreaker node, you can deploy a IBM Storage Scale Tiebreaker configuration on the same system with either the Primary or Mirror configuration. For highest availability, assign each configuration to separate cloud groups which do not share compute nodes. With this setup, the Tiebreaker node does not reside on the same compute node as the Primary or Mirror node, and failure of any one compute node cannot bring down two IBM Storage Scale instances at once.

As a further consideration, when locating the IBM Storage Scale Tiebreaker configuration on the same system with either the Primary or Mirror configuration, if one Cloud Pak System Software for Power instance is larger than the other, you might choose to locate the IBM Storage Scale Primary and Tiebreaker configurations on your largest system, and the IBM Storage Scale Mirror configuration on the smaller system.

Note also that the IBM Storage Scale Tiebreaker configuration must have IP connectivity to both the Primary and Mirror configurations.

For more information about configuring an active/active IBM Storage Scale deployment, see the Related link.