503 Slowdown errors for requests to s3://ecmwf-forecasts

AIFS, IFS and OpenIFS
1

Hi all,

Over the past few days, I’ve been noticing frequent 503 errors when requesting AIFS data from the s3://ecmwf-forecasts S3 bucket.

aws s3 cp --no-sign-request s3://ecmwf-forecasts/20251101/00z/aifs-ens/0p25/enfo/README.txt ~/Downloads/README.txt

gives back

download failed: s3://ecmwf-forecasts/20251101/00z/aifs-ens/0p25/enfo/README.txt to Downloads/README.txt An error occurred (SlowDown) when calling the GetObject operation (reached max retries: 2): Please reduce your request rate.

More complicated data requests are even less likely to succeed. Is there an overwhelming user request volume on that bucket?

Thanks,

Evan

2

Hi Evan,

This data storage is in charge of AWS, so we at ECMWF have no visibility if there is a bigger than usual demand on the service.

If it is of any help, when the download fails from AWS, you can try downloading directly from ECMWF, using opendata api Python client: GitHub - ecmwf/ecmwf-opendata: A package to download ECMWF open data

I hope this helps!

Milana