Hello everyone,

My company processes millions of requests for file uploads/downloads and we are looking at Nginx to replace Apache. We are running into a problem that I hope you can help -- I have searched the web and even read Nginx HTTP Server book by Clement Nedelcu.

At a high level, the flow of a request through our system is as follows: user agent posts the data to upload --> Ngixn acting as a reverse proxy --> Object store -> post action of passing request to Uwsgi.

Problem: when uploading a large file (~ 100MB) , the post action is failing. The error message seen in error.log is "8 sendfile() failed (9: Bad file descriptor) while sending request to upstream," message. This use case occurs even if no load on the system,

When I enable "debug", I see that after the Nginx streams the bytes to the object store, the temp file is deleted. When the post action is executed it fails as the temp file is gone.


*Note: this error is NOT seen when upload small files.

Details:
- Nginx version 1.1.17
- UWsgi vesrion 1.0
- Cent OS 2.6.32-131.0.15.el6.x86_64
- The relevant nginx configuration is:

##
# uri block to upload to object store.
##
location '/upload/objecststorage' {
proxy_pass https:/objectstore_host/valut
post_action /os/postback/ospostback.py;
}

location = '/os/postback/ospostback.py' {
root html/uwsgi;
set $app ospostback;

uwsgi_pass unix:/tmp/uwsgi.sock;
include uwsgi_params;

uwsgi_param SERVER_ADDR $server_addr;
uwsgi_param SCRIPT_NAME $app;
uwsgi_param UWSGI_MODULE $app;
uwsgi_param UWSGI_CALLABLE "${app}_handler";
uwsgi_param UWSGI_PYHOME $document_root;
uwsgi_param UWSGI_CHDIR $document_root;

uwsgi_param UWSGI_BYTES $body_bytes_sent;
uwsgi_param UWSGI_PATH $path;
uwsgi_param UWSGI_PID $proc_id;
uwsgi_param UWSGI_ID $token;
uwsgi_param UWSGI_KEY $arg_id;
uwsgi_modifier1 30;

}

Any help would be great. I really want to use Nginx but this is now a blocker issue for my company.

Regards