Hi,

I have:
nginx version: nginx/1.12.2 (github.com/istenrot/centos-nginx-http2: openssl-1.0.2m, PCRE JIT, PushStream, HeadersMore, LUA, Brotli)
built by gcc 4.9.2 20150212 (Red Hat 4.9.2-6) (GCC)
working as reverse proxy for ceph with media files

Here's my configuration.. (only the relevant part)

http {

proxy_temp_path /mnt/nginx-cache/temp_proxy 1 2;

proxy_cache_lock on;
proxy_cache_path /mnt/nginx-cache/ceph levels=1:2 keys_zone=myCache:256m inactive=8h max_size=30g;
proxy_cache_revalidate on;

proxy_request_buffering off;
proxy_buffering on;
proxy_buffers 64 16k; #for lua

sendfile on;
sendfile_max_chunk 512k;
aio threads;
directio 512k;
output_buffers 1 128k;

server {
listen 80;
server_name _;

location / {
proxy_pass http://ceph$uri;
proxy_set_header Host $host;
proxy_cache myCache;
}
}

cache is tmpfs:
tmpfs /mnt/nginx-cache tmpfs rw,size=40960m,noatime,uid=335,context="system_u:object_r:httpd_tmp_t:s0" 0 2


Now df -h shows: tmpfs 40G 35G 5.7G 86% /mnt/nginx-cache and deleted files in /mnt/nginx-cache/temp_proxy are about 200M

Strace of cache manager shows:
epoll_wait(9, [], 512, 1000) = 0
epoll_wait(9, [], 512, 1000) = 0
epoll_wait(9, [], 512, 1000) = 0
epoll_wait(9, [], 512, 1000) = 0
for most of the time

How to improve this situation?