COS launched the metadata acceleration feature to provide high-performance file system features. Metadata acceleration leverages of the powerful metadata management feature of Cloud HDFS (CHDFS) at the underlying layer to allow users to use file system semantics to access COS. The system design metrics can reach a bandwidth of up to 2.4 GB/s, over 100,000 queries per second (QPS), and a latency of milliseconds. Buckets with 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.
The following table compares the product feature support between enabling and not enabling metadata acceleration:
|Metric||Metadata Acceleration Enabled||Metadata Acceleration Disabled|
|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|
|Hotlink protection||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|
|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.
Currently, metadata acceleration is still in beta testing and is not billed. If billing is required in the future, we will notify you via Message Center, email, or SMS. You can check your message center or see Billing Overview to keep up with the latest billing plans.