In a Dell PowerScale cluster that consists of four A300 nodes and three F600 nodes, expanding both node pools requires adding nodes to each pool. The minimum number of nodes an engineer can add to expand both node pools is determined by the following factors:

Minimum Node Addition:

PowerScale clusters allow the addition of nodes one at a time to existing node pools.

However, to maintain balanced performance and capacity, it's recommended to add nodes in pairs or according to specific guidelines for each node type.

Node Pool Requirements:

A300 Nodes (Capacity Tier):

Designed for high-capacity storage needs.

Adding at leasttwo A300 nodeshelps maintain even data distribution and protection levels.

F600 Nodes (Performance Tier):

Designed for high-performance all-flash storage requirements.

Adding at leastone F600 nodecan expand the performance tier, but adding two would be optimal for balance.

Minimum Nodes to Expand Both Pools:

Option Dsuggests adding2xA300 and 1xF600, totalingthree nodes.

This is the minimum number among the options provided that allows expansion of both node pools.

Why Option D is Correct:

Meets Minimum Addition Recommendations:

Adding2xA300 nodesenhances capacity while maintaining data protection schemes like FEC (Forward Error Correction).

Adding1xF600 nodeincreases performance capacity with minimal investment.

Ensures Data Protection and Performance:

Adequate node addition helps in maintaining the cluster's data protection policies and performance characteristics.

References:

Dell PowerScale OneFS Administration Guide– Guidelines on adding nodes to existing clusters.

Dell PowerScale Best Practices– Recommendations for node additions and cluster expansions.

Dell PowerScale Technical Specifications– Details on node types and their roles within a cluster.