Issue Summary
Following the upgrade to AWS SDK v2 in Bamboo Data Center, S3 artifact downloads show a noticeable throughput reduction compared to older versions.
- AWS SDK v1 scheduled multipart download tasks across concurrent threads in parallel.
- AWS SDK v2 uses an asynchronous Netty HTTP client where multipart download chunks are requested sequentially via the subscriber stream model rather than concurrently.
This is a suggestion to explore optimizations to improve S3 artifact download concurrency/throughput within the AWS SDK v2 architecture (e.g. evaluating AWS CRT client tuning or concurrency configurations) for file transfers.
Steps to Reproduce
- Configure the Amazon S3 Artifact Handler in Bamboo Administration (Overview > Artifact Handlers).
- Run a build or deployment plan on a remote agent that downloads large artifacts from S3.
- Compare download throughput against Bamboo 9.6.x or direct S3 concurrent downloads.
Expected Results
S3 artifact downloads download concurrently with high multi-part throughput comparable to AWS SDK v1 or optimized concurrent S3 transfer clients.
Actual Results
Artifact download throughput is lower due to sequential multi-part chunk retrieval in the default AWS SDK v2 Netty HTTP client.
Workaround
Currently there is no known workaround for this behavior. A workaround will be added here when available