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Torch Object Storage

Data redundancy

Changing the redundancy type

You can enable multi-AZ redundancy when creating a bucket or for an existing bucket. This topic explains how to change the redundancy type of a bucket from single-AZ to multi-AZ.

tip

You can only change the redundancy type of buckets in China (Beijing), China (Shanghai), China (Guangzhou), and Asia Pacific (Johor).

Use cases

As your business grows, so does your need for data durability and service availability. At that point, relying on single-AZ data redundancy may no longer be sufficient. To enhance business stability and data reliability, you can change a bucket's redundancy type from single-AZ to multi-AZ.

Converting from single-AZ to multi-AZ redundancy is transparent to your applications and does not affect their availability. After conversion, TOS stores your data across three availability zones within the same region. This setup ensures that your storage service will remain stable, even if one zone fails.

Notes

Risks: Deleting a large number of objects and then performing List or GetFileStatus operations on the deleted range during the conversion process may result in increased API latency or timeouts. For this reason, we recommend pausing any relevant lifecycle rules before starting the conversion.

Scenarios where conversion is not supported:

Buckets with the following storage types: Archive, Cold Archive, or Deep Cold Archive.

Buckets that contain objects stored in Archive, Cold Archive, or Deep Cold Archive.

HNS or vector buckets. For more information about bucket types, see Bucket type and TOS Vectors overview.

Billing: You will be charged for multi-AZ redundancy once the conversion is complete. Multi-AZ redundancy is more expensive than single-AZ redundancy. For details on how much it costs to store data in more than one AZ, check out Storage.

Required permissions: By default, the owner of an account has full permissions. Identity and Access Management (IAM) users have no permissions by default. If an IAM user needs to perform this operation, the account owner must grant the user the tos:TOSFullAccess permission using an IAM or bucket policy.

Conversion direction: Only single-AZ buckets can be converted to multi-AZ redundancy. Conversion is irreversible. Proceed with caution.

Bucket size: You can only change the redundancy type for buckets containing fewer than 1 billion objects with a storage capacity of less than 100 TB. If you need to convert a larger bucket, contact your account manager.

Impacts on replication rules: When configuring cross-region or same-region replication between two buckets, converting one bucket's redundancy type will not automatically convert the other's.

Steps

In the left navigation pane, click Buckets.

On the Buckets page, click the name of the bucket.

In the left navigation pane, click Overview.

In the Basic information section, click Convert to multi-AZ redundancy.

Read the information, confirm the task details, and then click OK.

In the box that appears, verify the details and click OK.

Related operations

After submitting the task, click View details next to Redundant conversion status to view the task ID, task status, task creation time, task progress, and estimated remaining time.

The following table describes the task statuses for redundancy type conversion.

Task status	Description
In the queue	The task can be canceled. Conversion is expected to begin two to three hours after the task is successfully created. In special circumstances, the queuing time may be longer. The actual queuing time may vary.
Running now	The task cannot be canceled. The estimated conversion time is shown for reference only.
Conversion complete	The task can be deleted. Completed conversion tasks are retained for three months by default and are automatically deleted after that time. Conversion tasks in other statuses are not subject to the three-month retention limit.

Last updated: 2026.10.12 10:22:36