How to progress azcopy for file/disk size of 1TB?

Question

Hi,

When doing an azcopy from one storage to another, i am getting the "Service may be limiting speed" message and after some time the transfer will fail. The log message would contain:

503 The server is busy.. When Staging block from URL. X-Ms-Request-Id:

---Additional details----

Command run: azcopy cp --blob-type BlockBlob <Source URL indicated in Disk Export> <Target URL indicated by Storage account and Blob name>

azcopy version: 10.19.0
Source: Disk Export
Destination: Blob Storage
Size: 1TB
Tweaked variable: export AZCOPY_CONCURRENCY_VALUE=32
Other info: transfer works successfully for smaller files/disk (e.g. 30GB and 256GB)

https://learn.microsoft.com/en-us/azure/storage/common/storage-use-azcopy-optimize

----- end ---

Thanks for any suggestions/help.

Cheers.

Answer 1

@Gregorio Montaño

As per this documentation, this message is displayed if AzCopy is receiving "Server Busy" responses from Azure. (I.e. HTTP status 503). Seeing a few Server Busy messages is fine. AzCopy will automatically retry the affected operations, with an exponential delay.

Suggested steps in this case:

1. If the message is displayed only infrequently and intermittently, it's probably normal and can be ignored.
2. Otherwise, check your throughput against the publicly documented throughput and IOPS limits for the particular type of Storage Service that you are using. ( If using AzCopy at the default logging level, the number of IOPS achieved is shown near the end of the log file). If you are approaching the throughput or IOPS limits, then seeing this message is expected.
3. If you are not approaching the throughput or IOPS limits, and you are seeing this message persistently, then check the documentation on High Throughput Block Blobs and Premium Block Blobs. If, after checking that documentation, it appears that you should not be seeing this message, please reach out to the support.

Additional reading:

• https://github.com/Azure/azure-storage-azcopy/issues/380

If this doesn't help, it would help to get the following details to troubleshoot your issue further:

• The exact command line used, including the source and destination URLs
• The output of azcopy jobs show <job-id> --with-status=Failed
• The output of azcopy jobs resume <job-id> --with-status=Failed
• The output of azcopy jobs clean <job-id>

Alternatively, you can also check the link you provided (https://learn.microsoft.com/en-us/azure/storage/common/storage-use-azcopy-optimize), which is a guide on how to optimize azcopy performance. It has some tips on how to adjust the concurrency value, the number of parallel operations, and the block size to improve the speed and reliability of your data transfer.

You can also use the --log-level flag to get more detailed information about your azcopy operation.

Let me know in the comments and we can investigate further. Thanks.