PHP-FPM no nginx: o buffer do fastcgi não é grande o suficiente.
Tente adicionar isso à sua configuração:
fastcgi_buffers 8 512k;
fastcgi_buffer_size 256k;
fastcgi_send_timeout 5m;
fastcgi_read_timeout 5m;
fastcgi_connect_timeout 5m;
Minha configuração do nginx:
server {
client_max_body_size 100M;
listen 80;
server_name phpmyadmin.dev;
root /usr/share/phpmyadmin;
access_log off;
index index.php index.html index.htm;
location ~ ^/(.+\.php)$ {
try_files $uri = 404;
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include /etc/nginx/fastcgi_params;
fastcgi_buffers 8 512k;
fastcgi_buffer_size 256k;
fastcgi_send_timeout 5m;
fastcgi_read_timeout 5m;
fastcgi_connect_timeout 5m;
}
}