Docs

Torch Object Storage

Data redundancy

Multi-AZ redundancy

Certain TOS regions have multiple availability zones (AZ). Having multiple zones can provide your buckets with locally redundant availability and improved data durability. If you enable multi-AZ redundancy, TOS will store your data across three availability zones in the same region. This ensures that your storage service will be stable even if one zone fails.

tip

Multi-AZ redundancy is currently only available in China (Beijing), China (Shanghai), China (Guangzhou), and Asia Pacific (Johor).

Use cases

Multi-AZ redundancy provides data durability of 99.9999999999% (12 nines) and service availability of 99.995% for Standard Storage. It is ideal for scenarios that require high levels of data reliability and stability. Once multi-AZ redundancy has been enabled, other data centres will continue to provide stable storage services if a data centre fails due to extreme circumstances, ensuring the stability of your business and the reliability of your data.

Notes

Multi-AZ storage costs more than single-AZ storage. Once enabled, multi-AZ redundancy cannot be disabled. For details on how much it costs to store data in more than one AZ, check out Storage.

The following rules apply to storage types with a minimum billable unit requirement:

Standard Storage: For objects in a given region that are smaller than 64 KiB,

If the number of such objects reaches or exceeds 1 billion, each object will be billed as 64 KiB.

If the number remains below 1 billion, the objects are charged at their actual size.

Other storage types: Objects smaller than 64 KiB are charged as 64 KiB, and objects equal to or larger than 64 KiB are charged at actual size.

Supported storage types

Category	Standard Storage (multi-AZ)	Infrequent Access Storage (multi-AZ)	Intelligent Tiering (multi-AZ)	Flashback Archive (multi-AZ)
Designed data durability	99.9999999999% (12 nines)	99.9999999999% (12 nines)	99.9999999999% (12 nines)	99.9999999999% (12 nines)
Service availability	99.995%	99.5%	Uses the access tier of the object before the transition	99.5%
Minimum billable object size	64 KiB	64 KiB	None	64 KiB
Minimum storage duration	None	30 days	None	90 days
Storage cost	Standard	Lower	Based on the access frequency	Lower
Request cost	Standard	Higher	Higher, with additional object monitoring fees charged	Higher
Data retrieval cost	None	Per-GiB retrieval fees apply	None	Per-GiB retrieval fees apply
Data access	Real-time access with millisecond latency	Real-time access with millisecond latency	Real-time access with millisecond latency	Real-time access with millisecond latency
Parameter value	STANDARD	IA	INTELLIGENT_TIERING	ARCHIVE_FR

Using multi-AZ redundancy

Enable multi-AZ redundancy.

To enable multi-AZ redundancy when creating a bucket, see Creating buckets.

To change the redundancy type of an existing bucket, see the Steps section.

Upload an object.

To upload an object to a multi-AZ bucket, you can choose the storage type from the following options: Inherit Bucket, Standard Storage (Multi-AZ), Intelligent Tiering (Multi-AZ), Infrequent Access Storage (Multi-AZ), and Flashback Archive (Multi-AZ). For instructions, see Uploading objects.

Other operations

After enabling multi-AZ redundancy, you can do the following:

Operation	Description
View bucket redundancy type	You can check Redundancy type on the Buckets page. You can also check whether multi-AZ redundancy is enabled for a bucket by looking at the Basic information section on its Overview page. For instructions, see Viewing bucket overview.
View object storage type	You can view the object storage type in either the Objects list or the Basic information section of the Details panel.
Change object storage type	When modifying the object storage type, you can choose from the following options: Standard Storage (Multi-AZ), Intelligent Tiering (Multi-AZ), Infrequent Access Storage (Multi-AZ), and Flashback Archive (Multi-AZ). For instructions, see Changing object storage type.
Configure lifecycle rules	You can use lifecycle rules to transition the latest and historical versions of objects to one of the following storage types: Infrequent Access Storage (Multi-AZ), Intelligent Tiering (Multi-AZ), and Flashback Archive (Multi-AZ). For instructions, see Configuring lifecycle rules.
Move objects	You can move objects between single-AZ and multi-AZ buckets. Their redundancy type will automatically change to match that of the destination bucket. For instructions, see Moving objects.
Copy objects within one region	You can copy objects between single-AZ and multi-AZ buckets within the same region. Their redundancy type will automatically change to match that of the destination bucket. For instructions, see Copying objects.
Copy objects across regions	You can copy objects between single-AZ and multi-AZ buckets in different regions. Their redundancy type will automatically change to match that of the destination bucket. For instructions, see Cross-region replication.

Last updated: 2026.08.04 10:56:14