fix(clustered): clarify compactor scaling guidance for CPU and memory

Addresses customer confusion where scaling CPU alone doesn't improve
compactor performance. Compactor concurrency scales based on memory
allocation, not CPU count, so both resources should be scaled together.

Closes influxdata/DAR#514

add related links

content/influxdb3/clustered/admin/scale-cluster.md

@@ -8,9 +8,11 @@ menu:
     parent: Administer InfluxDB Clustered
     name: Scale your cluster
 weight: 207
-influxdb3/clustered/tags: [scale]
+influxdb3/clustered/tags: [scale, performance, Kubernetes]
 related:
   - /influxdb3/clustered/reference/internals/storage-engine/
+  - /influxdb3/clustered/write-data/best-practices/data-lifecycle/
+  - /influxdb3/clustered/query-data/troubleshoot-and-optimize/optimize-queries/
   - https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#requests-and-limits, Kubernetes resource requests and limits
 ---
 
@@ -559,11 +561,14 @@ concurrency demands or reaches the hardware limits of your underlying nodes.
 
 ### Compactor
 
-- **Recommended**: Maintain **1 Compactor pod** and use [vertical scaling](#vertical-scaling) (especially
-increasing the available CPU) for the Compactor.
+- **Recommended**: Maintain **1 Compactor pod** and use [vertical scaling](#vertical-scaling) for the Compactor.
+Scale CPU and memory resources together, as compactor concurrency settings scale based on memory, not CPU count.
 - Because compaction is a compute-heavy process, horizontal scaling increases compaction throughput, but not as
 efficiently as vertical scaling.
 
+> [!Important]
+> When scaling the Compactor, scale CPU and memory resources together.
+
 ### Garbage collector
 
 The [Garbage collector](/influxdb3/clustered/reference/internals/storage-engine/#garbage-collector) is a lightweight process that typically doesn't require