my.cnf

[mysqld]
slow_query_log
slow_query_log-file = /var/log/mysql/mysql-slow.sql
long_query_time = 5

datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0

max_allowed_packet=300M

innodb_buffer_pool_size = 1G # 8割説
innodb_flush_log_at_trx_commit = 0
innodb_flush_method=O_DIRECT

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

nginx.conf

worker_processes auto;

events {
    worker_connections  10240;
    # accept_mutex_delay 100ms;
    accept_mutex off;
}

http {
  upstream app {
    server 127.0.0.1:8080;
    keepalive 128;
  }

  include /etc/nginx/mime.types;

  server {
    log_format with_time '$remote_addr - $remote_user [$time_local] '
                         '"$request" $status $body_bytes_sent '
                         '"$http_referer" "$http_user_agent" $request_time';
    access_log /var/log/nginx/access.log with_time;

    root    /home/isucon/webapp/public/;

    location /stylesheets {
      # max: キャッシュの最大数
      # inactive: アクセスがないキャッシュの有効期限
      open_file_cache max=100 inactive=20s;
      expires 1d;
    }
    location /images {
      # max: キャッシュの最大数
      # inactive: アクセスがないキャッシュの有効期限
      open_file_cache max=100 inactive=20s;
      expires 1d;
    }

    location / {
      proxy_http_version 1.1;
      proxy_set_header Connection "";
      proxy_pass http://app;
    }
  }
}