This topic describes the types of error messages returned with HTTP status code 503, and the common causes and solutions to these errors.

DownloadTrafficRateLimitExceeded

  • Error message: Please reduce your upload request traffic.
  • Cause: The download traffic exceeds the limit.
  • Solution: Make sure that the download traffic does not exceed the limit. The default download traffic limit is is 5 Gbit/s. To adjust the limit, submit a ticket.

UploadTrafficRateLimitExceeded

  • Error message: Please reduce your upload request traffic.
  • Cause: The upload traffic exceeds the limit.
  • Solution: Make sure that the upload traffic does not exceed the limit. The default upload traffic limit is 5 Gbit/s. To adjust the limit, submit a ticket.

MetaOperationQpsLimitExceeded

  • Error message: Qps limit for the meta operation is exceeded.
  • Cause: The queries per second (QPS) exceeds the default limit.

    OSS limits the QPS for the following API operations:

    • Operations related to services, such as GetService (ListBuckets)
    • Operations related to buckets, such as PutBucket and GetBucketLifecycle
    • Operations related to CORS, such as PutBucketCORS and GetBucketCORS
    • Operations related to LiveChannel, such as PutLiveChannel and DeleteLiveChannel.
  • Solution: Perform the operation again after a few seconds.

ServiceUnavailable

  • Error message: Thread pool is almost full, please retry later.
  • Cause: The OSS server is busy.
  • Solution: Try again later.

TotalQpsLimitExceeded

  • Error message: Max total qps limit is exceeded.
  • Cause: The QPS exceeds the limit.
  • Solution: Limit the total QPS for your Alibaba Cloud account. The limit of the total QPS for a single account is 10,000. However, the actual values that can be achieved are different in different read and write modes:
    • Sequential read/write: 2,000 QPS

      If you upload a large number of objects whose names contain sequential prefixes such as timestamps and letters, multiple object indexes may be stored in a single partition. If too many requests are sent to query these objects, the response time may be slow. We recommend that you do not upload a large number of objects whose names contain sequential prefixes. For more information about how to change sequential prefixes to random prefixes, see OSS performance and scalability best practices.

    • Non-sequential read/write: 10,000 QPS

    If you require a higher QPS, contact technical support.

ActiveRequestLimitExceeded

  • Error message: Max active request limit is exceeded.
  • Cause: The number of concurrent requests exceeds the limit.
  • Solution: Contact technical support.

CpuLimitExceeded

  • Error message: Please reduce your request rate.
  • Cause: The CPU cores consumed by concurrent requests for IMG exceeds the limit.
  • Solution: Reduce the number of concurrent requests for IMG. If you want to increase the number of concurrent requests , contact technical support.