documentdb-storage
Installation
SKILL.md
Storage — Azure DocumentDB
Azure DocumentDB clusters use remote premium SSD storage. Two disk types are offered:
| Storage type | IOPS / bandwidth scaling | Max IOPS | CMK | Use it for |
|---|---|---|---|---|
| Premium SSD (v1) | Scales with disk capacity — bigger disk → higher IOPS | 20,000 | ✔️ | Legacy clusters, scenarios that require CMK |
| Premium SSD v2 | Decoupled from disk size — IOPS/bandwidth gated by compute tier | 80,000 | ❌ | New production clusters; any I/O-intensive workload |
Premium SSD v2 is the default recommendation for new clusters. It delivers up to a 12× performance boost at no added cost by removing the disk-size lever from the IOPS equation — you size storage for capacity and size compute for throughput, independently.
How Premium SSD v2 changes sizing
On Premium SSD v1, hitting 20,000 IOPS required provisioning a 20 TB disk even when only ~1 TB of data was stored. On Premium SSD v2, the highest achievable IOPS and bandwidth for the chosen compute tier are auto-configured regardless of disk size:
- Choose storage size based on how much data the cluster will hold.
- Choose compute tier based on how much IOPS / MBps the workload needs (see storage-tier-iops-caps).
- No knobs to tune — the upper-bound IOPS/bandwidth for the tier are applied automatically at no extra cost.