Storage Class Overview
Last updated: 2025-10-20 15:21:50
Storage class reflects the storage level and activity level of objects in Cloud Object Storage (COS). Based on access frequency and disaster recovery level, COS provides multiple storage types: MAZ_STANDARD, MAZ_STANDARD_IA, MAZ_ARCHIVE, MAZ_INTELLIGENT TIERING, INTELLIGENT TIERING, STANDARD, STANDARD_IA, ARCHIVE, and DEEP_ARCHIVE. Each storage type has varying characteristics, such as object access frequency, data durability, data availability, and access delay. Users can choose the storage type to upload data to COS based on their scenario.
Note:
If you did not specify the storage class when uploading an object, it will be uploaded to STANDARD by default.
For more information on multi-AZ, see Overview of Multi-AZ Feature.
MAZ_STANDARD/STANDARD
Both MAZ_STANDARD and STANDARD storage classes are highly reliable, available, and powerful object storage service designed for hot data and feature low latency and high throughput.
MAZ_STANDARD has higher data durability and service availability than STANDARD. It uses a different storage mechanism to store the data in different data centers in the same region, so as to prevent failures in one data center from affecting the entire service and further guarantee your business stability.
Use cases
Use cases involving lots of hotspot files or frequent data access, including trending videos, social images, mobile apps, game programs, and static websites.
The STANDARD storage class is designed for general use and covers most use cases. It is more cost-effective than MAZ_STANDARD.
However, MAZ_STANDARD has higher data durability and service availability, making it suitable for business scenarios with higher requirements, including key files, commercial data, and sensitive information.
MAZ_STANDARD_IA/STANDARD_IA
Both MAZ_STANDARD_IA and STANDARD_IA storage classes are highly reliable object storage services with low storage costs and access latency. They allow you to access the first byte in milliseconds at a reduced price, so you can retrieve data quickly without waiting. Unlike STANDARD, they involve data retrieval fees when you access data.
MAZ_STANDARD_IA uses a different storage mechanism from STANDARD_IA to store the data in different data centers in the same region, so as to prevent failures in one data center from affecting the entire service and further guarantee your business stability.
Use cases
Use cases with low access frequency (for example, 1 to 2 times per month), such as cloud disk data, big data analysis, government and enterprise data, low-frequency archives, and monitoring data.
Note:
Both MAZ_STANDARD_IA and STANDARD_IA have minimum storage requirements. If the storage duration is less than 30 days, the bill is calculated as 30 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, see Pricing | Cloud Object Storage.
MAZ_INTELLIGENT TIERING/INTELLIGENT TIERING
Objects in the MAZ_INTELLIGENT_TIERING storage class can be stored in two storage layers: MAZ_STANDARD and MAZ_STANDARD_IA. Objects in the INTELLIGENT_TIERING storage class can also be stored in two storage classes: STANDARD and STANDARD_IA. COS will automatically switch between storage classes based on the access frequency of such objects with no data retrieval fees incurred, which reduces your storage costs. For more information, see INTELLIGENT TIERING Overview.
MAZ_INTELLIGENT TIERING uses a different storage mechanism from INTELLIGENT TIERING to store the data in different data centers in the same region, so as to prevent failures in one data center from affecting the entire service and further guarantee your business stability.
Use cases
Use cases with uncertain data access patterns. If your business has tight controls on costs and is less sensitive to file reading performance, you can use MAZ_INTELLIGENT TIERING or INTELLIGENT TIERING to reduce costs.
Note:
For MAZ_INTELLIGENT_TIERING and INTELLIGENT_TIERING, objects are billed based on their actual sizes. For more information on pricing, see Pricing | Cloud Object Storage.
MAZ_ARCHIVE/ARCHIVE
MAZ_ARCHIVE and ARCHIVE belong to Cold Data Type, providing users with high reliability, extremely low storage cost, and long-term storage service. Both MAZ_ARCHIVE and ARCHIVE require a min 90-day storage time, and data recovery (unfreeze) is required before reading data.
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.
MAZ_ARCHIVE uses a different storage mechanism compared with ARCHIVE , storing data in different data centers in the same city to further guarantee business stability against failure influence of a single IDC.
Note:
For more information about object restoration, see Restoring Archived Objects.
The QPS for restoration requests is limited to 100.
Use cases
MAZ_ARCHIVE and ARCHIVE are suitable for business scenarios requiring long-term data preservation, such as archival data, medical imaging, scientific materials, compliance file archiving, lifecycle file archiving, operation log archiving, and remote disaster recovery.
Note:
Both MAZ_ARCHIVE and ARCHIVE have minimum limits for storage time and storage unit. If the storage time is less than 90 days, it will be counted as 90 days. Each stored file smaller than 64KB will be counted as 64KB, while files greater than or equal to 64KB will be charged based on actual size. For pricing information, please see Pricing | Cloud Object Storage.
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, 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, view 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, see Pricing | Cloud Object Storage.
Storage Class Comparison
Comparison Item | MAZ_STANDARD | MAZ_STANDARD_IA | MAZ_ARCHIVE | MAZ_INTELLIGENT TIERING | INTELLIGENT TIERING | STANDARD | STANDARD_IA | ARCHIVE | DEEP ARCHIVE |
Storage class parameter | MAZ_STANDARD | MAZ_STANDARD_IA | MAZ_ARCHIVE | MAZ_INTELLIGENT_TIERING | INTELLIGENT_TIERING | STANDARD | STANDARD_IA | ARCHIVE | DEEP_ARCHIVE |
Data durability | 99.9999999999% | 99.9999999999% | 99.9999999999% | 99.9999999999% | 99.999999999% | 99.999999999% | 99.999999999% | 99.999999999% | 99.999999999% |
Service availability | 99.995% | 99.95% | 99.50% | It changes with the transition of layers. When in the frequent access tier, service availability can refer to MAZ_STANDARD; when in the infrequent access tier, service availability can refer to MAZ_STANDARD_IA. | It changes with the transition of layers. When in the frequent access tier, service availability can refer to STANDARD; when in the infrequent access tier, service availability can refer to STANDARD_IA. | 99.99% | 99.90% | 99.00% | 99.00% |
Response | Milliseconds | Milliseconds | Restoration requires advance application. Recovery operations support three modes. Expedited retrieval mode: Recovery tasks can be completed in 1-5 minutes. Standard retrieval mode: Recovery tasks complete within 3-5 hours. Bulk retrieval mode: Recovery tasks complete within 5-12 hours. | Milliseconds | Milliseconds | Milliseconds | Milliseconds | Requires restoration in advance by using one of 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 by using one of two restoration modes: Standard: Restores an object within 12-24 hours. Bulk: Restores multiple objects within 24-48 hours. |
Minimum billable object size | Measured by actual object size | 64 KB | 64KB | Measured by actual object size | Measured by actual object size | Measured by actual object size | 64 KB | 64 KB | 64 KB |
Minimum storage duration | No limit | 30 days | 90 days | No limit | No limit | No limit | 30 days | 90 days | 180 days |
Supported regions | Currently only support Beijing, Shanghai, Guangzhou, Hong Kong (China), Singapore, and Shanghai Finance regions. | Currently only support Beijing, Shanghai, Guangzhou, Hong Kong (China), Singapore, and Shanghai Finance regions. | Currently only support Beijing, Shanghai, Guangzhou, Hong Kong (China), Singapore, and Shanghai Finance regions. | Only Beijing, Shanghai, Guangzhou, and Singapore | Currently, only Beijing, Nanjing, Shanghai, Guangzhou, Chengdu, Chongqing, Singapore, Tokyo, Frankfurt, and Virginia regions are supported. | All regions | All regions | Applicable to public cloud regions (excluding Jakarta) and financial cloud regions | Only Beijing, Nanjing, Shanghai, Guangzhou, Chengdu, Chongqing, Tokyo, and Singapore |
Storage fees | High | High | extremely low | Varied by the storage class after intelligent tiering | Varied by the storage class after intelligent tiering | Standard | Low | Very low | Ultra low |
Data retrieval fees | None | Rather low. Charged by the actual amount of data read | Relatively high, charge based on actual data volume. Fees vary by recovery mode. | None | 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 | Standard | Rather high | Standard. Data needs to be restored to MAZ_STANDARD. | Rather high. You will also be charged the INTELLIGENT TIERING object monitoring 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 ARCHIVE data, request fees for retrieving data will be incurred |
Data processing | Supported | Supported | Supported, but requires recovery first | Supported | 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.
If the object belongs to the archive type (such as ARCHIVE, DEEP ARCHIVE), it is required to restore to the standard type (such as STANDARD) before modifying other storage types. For details, see Restoring Archived Objects.
How each storage class can be transitioned is described as follows:
Storage Class | Available Target Storage Class | Settable Storage Type (Settlement From Hot to Cold, Not Allowed Backward) |
MAZ_STANDARD | MAZ_STANDARD_IA, MAZ_ARCHIVE, MAZ_INTELLIGENT_TIERING | MAZ_STANDARD > MAZ_STANDARD_IA> MAZ_INTELLIGENT_TIERING / MAZ_ARCHIVE |
MAZ_STANDARD_IA | MAZ_STANDARD, MAZ_ARCHIVE, MAZ_INTELLIGENT_TIERING | MAZ_STANDARD_IA> MAZ_INTELLIGENT_TIERING / MAZ_ARCHIVE |
MAZ_ARCHIVE | After restoration, you can change to MAZ_INTELLIGENT_TIERING, MAZ_STANDARD, or MAZ_STANDARD_IA. | None |
MAZ_INTELLIGENT_TIERING | MAZ_STANDARD, MAZ_STANDARD_IA, MAZ_ARCHIVE | None |
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, see the following documents:
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