Nginx automatically deletes cache which is set to be valid longer?

Question

I set up a Nginx reverse proxy server serving mp4 files hosted on another server. Everything is working fine now except the cache. Although I have proxy_cache_valid set to 1 day (proxy_cache_valid any 1d), the cache will always be automatically deleted after a short amount of time (5-10 mins I think). My file sizes range from 200 - 1500MB (700MB in average).

I couldn't figure out what's wrong with the configurations. Anything might help.

Here are the configurations:

worker_processes  auto;

worker_rlimit_nofile 100000;

events {
    worker_connections  5000;
    multi_accept on;
    use epoll;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;
    tcp_nopush     on;
    tcp_nodelay on;

    keepalive_timeout  10;
    keepalive_requests 1024;
    client_body_timeout 12;
    client_header_timeout 12;
    send_timeout 10;

    proxy_cache_path /tmp/mycache keys_zone=mycache:10m use_temp_path=off;
    limit_conn_zone $binary_remote_addr zone=addr:10m;
    server {
        listen       80;
        server_name  localhost;

    access_log off;

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

    open_file_cache max=10000 inactive=30s;
    open_file_cache_valid    60s;
    open_file_cache_min_uses 5;
    open_file_cache_errors   on;

    client_body_buffer_size 16K;
    client_header_buffer_size 1k;
    client_max_body_size 8m;
    large_client_header_buffers 2 1k;

        location / {
        proxy_cache mycache;
        proxy_max_temp_file_size 1924m;
        slice              100m;
        proxy_cache_key    $host$uri$slice_range;
        proxy_set_header   Range $slice_range;
        proxy_http_version 1.1;
        proxy_ignore_headers X-Accel-Expires Expires Cache-Control Set-Cookie; 
        proxy_cache_valid  any 1d;
        limit_conn addr 5;
        proxy_pass   http://domain2.com/;
        secure_link $arg_md5,$arg_expires;
        secure_link_md5 "secret$secure_link_expires$uri";

        if ($secure_link = "") { return 403; }
                if ($secure_link = "0") { return 410; }
        }

    }

}

Answer 1

Your issue can be solved by modifying the proxy_cache_path setting in your Nginx config. Here you define your store to hold your cache objects. There is a inactive=time option would fix that:

Cached data that are not accessed during the time specified by the inactive parameter get removed from the cache regardless of their freshness. By default, inactive is set to 10 minutes.

In your example I would extend the minimum time to 2 days:

proxy_cache_path /tmp/mycache keys_zone=mycache:10m use_temp_path=off inactive=2d;