COS offers the INTELLIGENT TIERING, STANDARD, STANDARD_IA, ARCHIVE, and DEEP ARCHIVE storage classes for objects with different access frequency and disaster recovery levels. They indicate how active objects are in COS, and vary from one another in access frequency, durability, availability, latency, and more. You can choose which storage class to upload your objects to as needed.

Note：

• If you did not specify the storage class for an object upon upload, it will be uploaded to STANDARD by default.

ARCHIVE

COS ARCHIVE is a highly reliable object storage service designed for cold data, and offers very low storage costs and long-term data retention. This storage class has a minimum storage duration of 90 days. To read data stored in ARCHIVE, you need to restore it to STANDARD first.

COS supports the following three restoration modes for ARCHIVE:

• Expedited: restores an object within 1-5 minutes.
• Standard: restores an object within 3-5 hours.
• Bulk: restores objects within 5-12 hours.

Note：

• For more information about object restoration, please see Restoring Archived Objects.
• The QPS for restoration requests is limited to 100.

Use cases

Use cases that require long-term data retention, such as archival data, medical images, scientific data and other compliance files, lifecycle files, logs, and remote disaster recovery.

Note：

ARCHIVE has minimum storage requirements. If the storage duration is less than 90 days, the bill is calculated as 90 days. Likewise, if the size of a file is smaller than 64 KB, the bill is calculated as 64 KB (if the size of a file is greater than or equal to 64 KB, the bill is calculated based on the actual file size). For more information, please see COS Pricing.

DEEP ARCHIVE

COS DEEP ARCHIVE is a highly reliable object storage service that offers the lowest storage costs and long-term data retention. This storage class has a minimum storage duration of 180 days. To read data stored in DEEP ARCHIVE, you need to restore it to STANDARD first. For more information, please see Overview - DEEP ARCHIVE.

COS supports the following two restoration modes for DEEP ARCHIVE:

• Standard: retrieves an object within 12-24 hours.
• Bulk: retrieves multiple objects within 24-48 hours.

Note：

The QPS of data restoration requests is limited to 100.

Use cases

Use cases that require long-term data retention, such as medical images, security monitoring data, and logs.

Note：

DEEP ARCHIVE has minimum storage requirements. If the storage duration is less than 180 days, the bill is calculated as 180 days. Likewise, if the size of a file is smaller than 64 KB, the bill is calculated as 64 KB (if the size of a file is greater than or equal to 64 KB, the bill is calculated based on the actual file size). For more information, please see COS Pricing.

Storage Class Comparison

Metric	INTELLIGENT TIERING	STANDARD	STANDARD_IA	ARCHIVE	DEEP ARCHIVE
Durability	99.9999999 99%	99.9999999 99%	99.9999999 99%	99.9999999 99%	99.9999999 99%
Availability	99.99%	99.95%	99.9%	99.9%	99.9%
Response	Milliseconds	Milliseconds	Milliseconds	Requires restoration in advance using one of these three restoration modes: Expedited: restores an object within 1-5 minutes. Standard: restores an object within 3-5 hours. Bulk: restores multiple objects within 5-12 hours.	Requires restoration in advance using either of these restoration modes: Standard: restores an object within 12-24 hours. Bulk: restores multiple objects within 24-48 hours.
Minimum billable object size	64 KB. Objects with sizes smaller than 64 KB are stored in the STANDARD tier	Calculated by the actual object size	64 KB	64 KB	64 KB
Minimum storage duration	30 days	No limit	30 days	90 days	180 days
Supported regions	Only Beijing, Shanghai, Guangzhou, Chongqing, and Tokyo	All regions	All regions	Only public cloud regions	Only Beijing, Shanghai, Guangzhou, Nanjing, Chengdu, and Tokyo
Storage fees	Differ depending on the storage class after intelligent tiering	Standard	Low	Very low	Ultra-low
Data retrieval fees	None	None	Rather low. Charged by the actual amount of data read	Rather high. Charged by the actual amount of data restored depending on the restoration mode	High. Charged by the actual amount of data restored depending on the restoration mode
Request fees	Rather high. You will also be charged the INTELLIGENT TIERING object monitoring fees	Standard	Rather high	Standard (the data needs to be restored to STANDARD first)	High (the data needs to be restored to STANDARD first). To retrieve DEEP ARCHIVED data, request fees for retrieving data will be incurred
Data processing	Supported	Supported	Supported	Supported (requires data restoration first)	Supported (requires data restoration first)

Storage Class Transition

COS offers various storage classes to indicate how active objects are in COS. You can still change the storage class for objects as needed, or transition objects to a less active storage class such as STANDARD_IA, ARCHIVE, or DEEP ARCHIVE.

Note：

• When transitioning objects, ensure that the target storage class is supported for the region where your object resides.
• To modify the storage class of an object stored in ARCHIVE or DEEP ARCHIVE, you need to restore it first into STANDARD. For more information, see Restoring an Archived Object.

How each storage class can be transitioned is described as follows:

Storage Class	Available Target Storage Class	Transition Priority
INTELLIGENT TIERING	STANDARD, STANDARD_IA, ARCHIVE, DEEP ARCHIVE	INTELLIGENT TIERING > ARCHIVE > DEEP ARCHIVE
STANDARD	INTELLIGENT TIERING, STANDARD_IA, ARCHIVE, DEEP ARCHIVE	STANDARD > STANDARD_IA > INTELLIGENT TIERING > ARCHIVE > DEEP ARCHIVE
STANDARD_IA	INTELLIGENT TIERING, STANDARD, ARCHIVE, DEEP ARCHIVE	STANDARD_IA > INTELLIGENT TIERING > ARCHIVE > DEEP ARCHIVE
ARCHIVE	INTELLIGENT TIERING, STANDARD, STANDARD_IA, DEEP ARCHIVE (after restoration)	ARCHIVE > DEEP ARCHIVE
DEEP ARCHIVE	INTELLIGENT TIERING, STANDARD, STANDARD_IA, ARCHIVE (after restoration)	None

For detailed directions, please see the following documents:

• Modifying Storage Classes
• Setting Lifecycles