Nginx 缓存节点的 %sys 利用率过高

Nginx 缓存节点的 %sys 利用率过高

我们设置了 Nginx 和 Lua(openresty 包)作为文件共享服务器的本地缓存节点,我们将文件分成“每 50MB”的块(通过方法)并将它们存储在缓存中以提高其效率。在低流量时,它工作正常,但随着缓存文件和负载的增加(即使它不是很高),缓存将变得无响应,因为大多数时候系统购买率 >80%。那么在这种情况下,什么可能是性能杀手

虽然我们尝试调整了几个参数(例如缓存目录级别、RAID 参数),但我还没有给出最佳解决方案

附言:当缓存中只有 10000 个文件并且服务器上的连接数约为 300/s 时,症状就会开始出现

缓存服务器规格

    1xCPU 2.5 Ghz 12 Cores
    128GB RAM
    10x500GB Samsung SSD RAID0 (128KB chuck s) storage
    linux Os -CentOS 6.6 64bit 
    File system ext4 4k block   

Nginx 配置

 worker_processes  auto;

events {

    use epoll;
    worker_connections 1024;
    multi_accept on;
 }


http {
    include       /usr/local/openresty/nginx/conf/mime.types;

    proxy_cache_path  /mnt/cache/ levels=2:2:2 keys_zone=default:1000m loader_threshold=100 loader_files=2000
                     loader_sleep=10 inactive=1y max_size=3500000m;
    proxy_temp_path /mnt/temp2 2 2;
    client_body_temp_path /mnt/temp 2 2;
    limit_conn_zone $remote_addr$uri zone=addr:100m;

    map $request_method $disable_cache {
      HEAD  1;
      default   0;
    }

    lua_package_path "/opt/ranger/external/lua-resty-http/lib/?.lua;/opt/ranger/external/nginx_log_by_lua/?.lua;/opt/ranger/external/bitset/lib/?.lua;;";

    lua_shared_dict file_dict  50M;
    lua_shared_dict log_dict   100M;
    lua_shared_dict cache_dict 100M;
    lua_shared_dict chunk_dict 100M;


    proxy_read_timeout 20s;
    proxy_send_timeout 25s;
    reset_timedout_connection on;

    init_by_lua_file '/opt/ranger/init.lua';

    # Server that has the lua code and will be accessed by clients
    server {
      listen       80 default;
      server_name  _;
      server_name_in_redirect off;

      set $ranger_cache_status $upstream_cache_status;

      lua_check_client_abort on;
      lua_code_cache on;

      resolver ----;
      server_tokens off;
      resolver_timeout 1s;

      location / {
        try_files $uri $uri/ index.html;
      }

      location  ~* ^/download/ {
        lua_http10_buffering off;
        content_by_lua_file '/opt/ranger/content.lua';
        log_by_lua_file '/opt/ranger/log.lua';
        limit_conn addr 2;
      } 
    }

    # Server that works as a backend to the lua code
    server {
      listen 8080;

      server_tokens off;
      resolver_timeout 1s;

      location  ~* ^/download/(.*?)/(.*?)/(.*) {
        set $download_uri  $3;
        set $download_host $2;
        set $download_url http://$download_host/$download_uri?$args;
        proxy_no_cache $disable_cache;
        proxy_cache_valid 200 1y;
        proxy_cache_valid 206 1y;
        proxy_cache_key "$scheme$proxy_host$uri$http_range"; 
        proxy_cache_use_stale error timeout http_502;
        proxy_cache default; 
        proxy_cache_min_uses 1;

        proxy_pass $download_url;
      }
    }
}

答案1

感谢@myaut 的指导,我查了一下, _spin_lock_irqsave 结果发现它与内核本身有关,而与 Nginx 无关。

根据文章中提到,可以通过禁用修复该问题的 RedHat Transparent Huge Page 功能来解决该问题。

echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled

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