Metadata Acceleration Overview

Last updated: 2021-11-24 12:07:03

    COS launched the metadata acceleration feature to provide high-performance file system features. Metadata acceleration leverages Cloud HDFS (CHDFS)’s powerful metadata management feature at the underlying layer to allow users to use file system semantics to access COS. The system design metrics can have a bandwidth of up to 2.4 GB/s, a 100,000-level QPS, and millisecond-level latency. A metadata acceleration−enabled can be widely used in scenarios such as big data, high-performance computing, machine learning, and artificial intelligence.

    If you haven’t enabled metadata acceleration for a bucket, it cannot accelerate metadata access by default and does not support access with POSIX file semantics, making it less favorable in terms of file LIST and not support RENAME. After enabling metadata acceleration, you can use POSIX file semantics to access objects in buckets through native COS APIs or the Hadoop tool deployed on the client side, the console, or SDKs.


    Metadata acceleration can only be enabled upon bucket creation and cannot be disabled once enabled. Please think twice before enabling it.

    Use Limits

    The following table compares the product feature support between enabling and not enabling metadata acceleration:

    Metric Metadata Acceleration Enabled Metadata Acceleration Disabled
    Creating/Querying/Deleting buckets Supported Supported
    Uploading/Downloading/Deleting objects Supported Supported
    Setting bucket permissions Supported Supported
    Setting object permissions Not supported (inherit from bucket permissions) Supported
    Intra-region disaster recovery Not supported Supported
    Bucket encryption Not supported Supported
    Object encryption Not supported Supported
    CORS Not supported Supported
    Hotlink protection Not supported Supported
    Versioning Not supported Supported
    Cross-bucket replication Not supported Supported
    Static websites Not supported Supported
    Origin-pull configurations Not supported Supported
    Lifecycle Only STANDARD-to-ARCHIVE transition is supported Supported
    Inventory Not supported Supported
    Bucket tagging Not supported Supported
    COS Select Not supported Supported
    COS batch operation Not supported Supported
    CI features Not supported Supported

    We are continuously optimizing metadata acceleration and will gradually support the product features above.

    Billing Description

    Currently, metadata is still in beta testing and is not billed. If billing should be required in the future, we will notify you via Message Center, emails, or SMS. You can check your message center or see Billing Overview to keep up with the latest billing plans.