PowerScale OneFS 9.8.0.0 Web Administration Guide

Node pools

A node pool is a group of three or more nodes that forms a single pool of storage. As you add nodes to the cluster, OneFS attempts to automatically provision the new nodes into node pools.

To autoprovision a node, OneFS requires that the new node be equivalent to the other nodes in the node pool. If the new node is equivalent, OneFS provisions the new node to the node pool. All nodes in a node pool are peers, and data is distributed across nodes in the pool. Each provisioned node increases the aggregate disk, cache, CPU, and network capacity of the cluster.

We strongly recommend that you let OneFS handle node provisioning. However, if you have a special requirement or use case, you can move nodes from an autoprovisioned node pool into a node pool that you define manually. The capability to create manually-defined node pools is available only through the OneFS command-line interface, and should be deployed only after consulting with Dell PowerScale Technical Support.

If you try to remove a node from a node pool for the purpose of adding it to a manual node pool, and the result would leave fewer than three nodes in the original node pool, the removal fails. When you remove a node from a manually-defined node pool, OneFS attempts to autoprovision the node back into an equivalent node pool.

If you add fewer than three equivalent nodes to your cluster, OneFS cannot autoprovision these nodes. In these cases, you can add new node types to existing node pools. Adding the new node types can enable OneFS to provision the newly added nodes to a compatible node pool.

Node pools can use SSDs either as storage or as L3 cache, but not both, with the following exception. PowerScale F200 and F600 nodes are full SSD nodes and can only be used as storage. Enabling L3 cache on F200 and F600 nodes is not an option.