Reference
Object storage pricing glossary
These terms are separate because vendors bill them separately. Collapsing them into one price per TB-month hides the conditions that matter during a restore.
Page updated .
Terms
Egress: Data transferred out of a storage provider to the internet or another destination. It is a network-transfer meter, separate from any fee for reading data from a cold class. Source: Cloudflare R2 docs: Pricing; checked 26 July 2026.
Retrieval: The processing or data-access charge for reading an object from an infrequent or archive class. It can apply in addition to request charges and egress, and some archive classes require a restore step before data can be read. Sources: Cloudflare R2 docs: Pricing and Amazon S3 docs: Understanding and managing S3 storage classes; checked 26 July 2026.
Class A operations: A vendor-defined bucket of API requests that usually create, list or mutate state. Cloudflare R2 puts operations such as PutObject, CopyObject and ListObjects in Class A, but the exact membership must come from each vendor. Source: Cloudflare R2 docs: Pricing; checked 26 July 2026.
Class B operations: A vendor-defined bucket of API requests that usually read existing state. Cloudflare R2 includes GetObject and HeadObject in Class B, so a restore can generate Class B requests even when egress itself is free. Source: Cloudflare R2 docs: Pricing; checked 26 July 2026.
Minimum storage duration: The shortest period for which an object is billed in a storage class. Reading an object does not end that period; deleting, replacing, moving or transitioning it early may create a charge for the remaining time. Source: Google Cloud Storage pricing; checked 26 July 2026.
Early deletion: The charge for ending or changing storage before the class's minimum duration has elapsed. It is triggered by actions such as deletion, overwrite, move or transition, not by a read-only restore that leaves the source object unchanged. Sources: Google Cloud Storage pricing and Azure docs: Blob rehydration from the archive tier; checked 26 July 2026.
Minimum billable capacity: An account-level storage floor that is charged even when actual stored data is smaller. Wasabi Pay-Go bills a 1 TB, 1024 GB, monthly minimum, including when the account stores less than that amount. Source: Wasabi docs: Monthly minimum storage charge; checked 26 July 2026.
Minimum billable object size: The smallest storage quantity billed for each object in a class. AWS S3 Standard-IA and One Zone-IA accept smaller objects but bill each as at least 128 KB. Source: AWS: Amazon S3 pricing; checked 26 July 2026.
Object lock: A retention control that can prevent a specified object version from being deleted or overwritten for a fixed period or under a legal hold. Its exact protection depends on versioning, retention mode and permissions. Source: Amazon S3 docs: Locking objects with Object Lock; checked 26 July 2026.
Immutability: The property that protected data cannot be changed or deleted during the applicable retention rule. It is a behavior to verify, not a synonym for ordinary versioning or a marketing label. Source: Amazon S3 docs: Locking objects with Object Lock; checked 26 July 2026.
WORM: Write once, read many. A WORM control allows data to be written and read while preventing the protected version from being overwritten or deleted under its retention rule. Source: Amazon S3 docs: Locking objects with Object Lock; checked 26 July 2026.
Storage class: A per-object tier that changes pricing, access behavior, minimum duration and retrieval treatment. The same provider can therefore have several offers that are not interchangeable for a backup workload. Source: Google Cloud Storage docs: Storage classes; checked 26 July 2026.
Rehydration: The process of making archived data readable in an online tier, either by copying it or changing its tier where the provider permits. It can have a priority, delay, read-request charge and retrieval charge separate from later egress. Source: Azure docs: Blob rehydration from the archive tier; checked 26 July 2026.
GB vs GiB: GB is decimal, 1,000,000,000 bytes; GiB is binary, 1,073,741,824 bytes. Some vendors use GB for the binary size: AWS bills S3 storage in a GB of 1,073,741,824 bytes. Backup Storage Prices preserves the vendor's unit and names any conversion, including Wasabi's published division of $7.99 by 1024 to reach $0.0078 per GB-month. Sources: NIST: Definitions of the binary prefixes, AWS: Amazon S3 pricing and Wasabi: Pay as you go pricing FAQs; checked 26 July 2026.