civetweb is hitting a limit (number of threads 1024)
When setting "rgw thread pool size" to a number higher than 1024 and enabling civetweb 'rgw_frontends="civetweb port=80"', civetweb does not work because of "MAX_WORKER_THREADS" value in civetweb.c
#1 Updated by Mustafa Muhammad about 9 years ago
The problem is in  as:
#define MAX_WORKER_THREADS 1024
I changed this to "MAX_WORKER_THREADS 20480" and it worked well.
I opened an issue upstream , and they fixed it .
I tried to make a pull request for your copy but after forking, I noticed that the pull request is for the deprecated repo:
Not the active upstream:
I think this should be fixed too