Block storage pricing compared: EBS vs Azure Disk vs OCI Block Volume
Capacity is the cheap part. This is how AWS EBS, Azure Managed Disks, and OCI Block Volume actually price capacity, IOPS, and throughput — and where the models diverge.
Block storage looks like a commodity until you need performance. Every provider will sell you a gigabyte for a few cents; the difference is what happens when that gigabyte has to serve 20,000 IOPS. The three vendors take genuinely different approaches, and the cheapest one depends entirely on which side of that line your workload sits.
Three different pricing models
| Provider | Baseline tier | How performance is priced |
|---|---|---|
| AWS EBS | gp3 SSD, ~$0.08/GB-month | 3,000 IOPS and 125 MB/s included; extra IOPS and throughput billed separately. io2 for high-durability, IOPS-heavy work at a premium. |
| Azure Managed Disks | Premium SSD v2, ~$0.08/GB-month | Capacity, IOPS, and throughput each metered independently. Legacy Premium SSD (P-series) instead sells fixed size/performance bundles. |
| OCI Block Volume | ~$0.0255/GB-month | Performance sold as VPUs (volume performance units) at ~$0.0017 per GB per VPU-month. Balanced (10 VPU) is the common default. |
Figures are public on-demand list prices in US regions, gathered August 2026. Discounts (committed use, reserved capacity, EDP/enterprise agreements) change the picture materially — always confirm against the provider's live calculator before deciding.
A worked example: 2 TB, balanced performance
Take a fairly ordinary database volume: 2 TB of SSD-class storage with moderate, steady IOPS demand rather than burst-heavy spikes.
| Provider | Configuration | Approx. monthly |
|---|---|---|
| AWS EBS gp3 | 2,048 GB, included 3,000 IOPS / 125 MB/s | ~$164 |
| Azure Premium SSD v2 | 2,048 GB, 3,000 IOPS, 125 MB/s | ~$170 |
| OCI Block Volume | 2,048 GB, Balanced (10 VPU) | ~$87 |
At baseline performance, OCI's blended capacity-plus-VPU model comes out roughly 45–50% lower at list price. That gap is consistent enough across sizes that storage-heavy estates are, alongside egress, the other place where a cross-provider look is usually worth the effort.
Where the ranking flips
- Very high IOPS per GB: small volumes needing extreme IOPS suit AWS io2 or Azure Ultra Disk, where you buy IOPS almost independently of capacity. OCI's VPU model ties performance to provisioned size, so tiny-but-fast volumes get expensive.
- Bursty, mostly-idle volumes: AWS gp3's included baseline is generous for workloads that idle most of the day.
- Snapshots and backups: snapshot storage is a separate meter everywhere and frequently exceeds the cost of the live volume. Retention policy is a pricing decision.
- Attached vs detached: an unattached volume still bills at full rate on all three. Orphaned volumes are one of the most common sources of waste we see on real bills.
The practical checklist
- Inventory volumes by size, provisioned IOPS, and actual observed IOPS — provisioned is almost always well above observed.
- Right-size before you compare providers; migrating over-provisioned storage just moves the waste.
- Price snapshots and cross-region copies as their own line, not as a percentage add-on.
- Check whether your workload needs the durability tier you're paying for — many gp3 estates run on io-class disks out of habit.