Practical guide
Right-size Hyperdisk performance cost
Avoid pricing Hyperdisk only by capacity when a configured IOPS or throughput setting is also billable.
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Price the configured performance, not the average chart
Hyperdisk can separate capacity from performance configuration. Google documents provisioned-performance charges for Hyperdisk and Extreme Persistent Disk; Hyperdisk Balanced supports configured IOPS and throughput, while Hyperdisk ML supports configurable throughput. A utilization graph that averages below the limit does not, by itself, reduce the provisioned setting billed for the month.
Consider a rate-free example. A 2 TiB volume is configured with 20,000 IOPS and 500 MiB/s for 730 hours. The estimate has three quantities: 2 TiB × 730 capacity-hours, 20,000 × 730 IOPS-hours when applicable, and 500 × 730 throughput-hours when applicable. Apply the correct regional rates and any included amounts from the price sheet. Do not replace 20,000 with an observed average of 3,000 unless the configuration is actually lowered.
Find a safe configuration floor
Review peak latency, IOPS, and throughput during the busiest reliable period, including backup, batch, and recovery traffic. Check application and VM limits as well as disk limits; Google notes Persistent Disk performance can depend on total attached capacity and VM vCPU count. Leave capacity for realistic growth, then test a lower setting in a controlled environment before changing production.
Use different scenarios for a steady database, bursty analytics scratch volume, and ML volume. A performance increase may be less expensive than scaling an entire VM fleet, but only measured workload behavior can establish that tradeoff.
The Persistent Disk / Hyperdisk Cost Calculator makes capacity and performance assumptions visible. Its result excludes snapshots, VM compute, and network charges.
FAQ
Does every disk have configurable IOPS and throughput billing?
No. Confirm the disk type and its documented pricing model before adding performance lines.
Can I delete an idle disk to save money?
Only after verifying that it is not a needed boot, data, recovery, or retained backup volume.