The metadata acceleration feature is a high-performance file system feature provided by Tencent Cloud Object Storage (COS). The metadata acceleration feature uses the excellent metadata management capabilities of Cloud HDFS (CHDFS) at its core, allowing users to access COS through file system semantics. The system is designed to achieve bandwidth of hundreds of GB/s, hundreds of thousands of QPS, and millisecond-level latency. After you enable the metadata acceleration feature for a bucket, the bucket can be widely used in scenarios such as big data, high-performance computing, machine learning, and AI.
Buckets without the metadata acceleration feature enabled have no metadata access acceleration by default, do not support access through POSIX file semantics, have bottlenecks in file LIST performance, and do not support file RENAME operations. After you enable the metadata acceleration feature, you can access files in a bucket through POSIX file semantics using the native COS API, or through Hadoop tools deployed on the client, the console, or SDKs.
Note:
The metadata acceleration feature can only be enabled when you create a bucket, and cannot be disabled after being enabled. Carefully consider whether to enable this feature based on your business requirements.
The metadata acceleration feature is currently in beta. To apply for beta access, please contact us. Note that if you need to perform a large number of reads and writes using COS semantics, we do not recommend enabling the metadata acceleration feature to ensure optimal performance. The metadata acceleration feature does not enable ATime by default. If you want to use ATime, note that metadata acceleration cannot guarantee the accuracy of ATime updates. Therefore, features that depend on ATime (such as lifecycle management) may also be subject to this limitation, and you need to carefully evaluate the impact of ATime inaccuracy. If you have a strong dependency on ATime, you can use the log feature for analysis. If you still want to enable this feature after evaluation, please contact us. Supported Region
The regions that currently support metadata acceleration buckets are as follows:
Chinese mainland: Beijing, Shanghai, Guangzhou, Nanjing, Chengdu, and Chongqing.
Hong Kong (China) and outside Chinese mainland: Hong Kong (China), Singapore, Tokyo, Japan, Jakarta, Indonesia, Bangkok, Thailand, Frankfurt, Germany, Silicon Valley, United States (US West), Virginia, United States (US East), and Sao Paulo, Brazil.
Use Limits
The following table lists the support status of related product features after the metadata acceleration feature is enabled for a bucket:
|
Bucket creation, query, and deletion operations | Supported Note: After you initiate a request to delete a metadata acceleration bucket, the backend marks the bucket as being deleted and performs the deletion operation asynchronously. The bucket remains visible until the deletion is complete. If you need to speed up the process, for example, to create a bucket with the same name immediately after deletion, please contact us. | Supported |
Object upload/download/delete operations | Supported Note: Custom headers x-cos-meta-* are not supported currently. | Supported |
Object listing operations | Supported Note: A metadata acceleration bucket supports only a directory as the prefix input parameter. When a listing is performed, it prints only the files at that level and does not recurse into subdirectories. | Supported |
Bucket permissions | Supported | Supported |
Object permissions | Inherits bucket permissions by default | Supported |
Data retrieval | Only standard retrieval mode is supported | Supported |
Intra-city disaster recovery | Supported | Supported |
Bucket Encryption (encryption) | Supports SSE-COS | Supported |
Object encryption | Supported | Supported |
Cross-origin resource sharing (CORS) | Supported | Supported |
Hotlink Protection | Not applicable | Supported |
Versioning | Not applicable | Supported |
Bucket replication | Not applicable | Supported |
Static website | Not applicable | Supported |
Origin-pull configuration | Not applicable | Supported |
Lifecycle | Supported | Supported |
Recycle bin | | Supported |
Data restoration | Only standard rehydration is supported. | Supported |
Inventory | In public beta. To request access to the inventory feature, contact us. | Supported |
Bucket tagging | Supported | Supported |
Object tagging | Not applicable | Supported |
COS Select | Not applicable | Supported |
COS Batch | Not applicable | Supported |
CI feature | Not applicable | Supported |
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