map slow after using render_list

Hi,

pretty much a newbie to OSM.

I managed to set up my own mapserver with mapnik and mod_tile. Everything works “fine”, albeit quite slow.
I thought I could speed things up substantially by using render_list, which would pregenerate tiles and make them load (almost) instantly.

Yet, after render_list was done, the maps load as slow as ever. My map is complete, but loads slow.

renderd shows these kind of messages constantly:

Aug 06 15:32:20 mapserver renderd[1602]: WARNING: Failed to send render cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Failed to read cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Connection 0, fd 7 closed, now 0 left
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got incoming connection, fd 7, number 1
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got incoming request with protocol version 2
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got command Dirty fd(7) xml(default), z(12), x(2139), y(1439), mime(image/png), options()
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Sending NotDone response(4)
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Sending render cmd(4 default 12/2139/1439) with protocol version 2 to fd 7
Aug 06 15:32:20 mapserver renderd[1602]: WARNING: Failed to send render cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Failed to read cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Connection 0, fd 7 closed, now 0 left
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got incoming connection, fd 7, number 1
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got incoming request with protocol version 2
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Got command Dirty fd(7) xml(default), z(12), x(2139), y(1436), mime(image/png), options()
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Sending NotDone response(4)
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Sending render cmd(4 default 12/2139/1436) with protocol version 2 to fd 7
Aug 06 15:32:20 mapserver renderd[1602]: WARNING: Failed to send render cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Failed to read cmd on fd 7
Aug 06 15:32:20 mapserver renderd[1602]: DEBUG: Connection 0, fd 7 closed, now 0 left

I’m not exactly sure what to make of it. I’m only displaying Switzerland, but my server might still be a bit on the weak side with 8 GB of RAM, 1 core and a HDD.