For registry operations, these were the numbers found at time the PR was written:
download_blob 108 per second across fleet
v2_auth 180 per second across fleet
catalog 1 per second across fleet
fetch_manifest 205 per second across fleet
list_all_tags 150 per second across fleet
With an average fleet size of 25. As a result, we went with a registry limit of 10r/s (10 * 25 = 250 requests) to bound even the most prolific puller.
Fixes https://jira.coreos.com/browse/QUAY-976
nginx's gzip module will ignore the content-length header on the HEAD request and try to gzip the body.... but there is no body, so it simply writes no header at all.
Code to turn this off was based off of https://trac.nginx.org/nginx/ticket/261
