[Tilesathome] t at h server performance

[milenko at king-nerd.com]

What's the disadvantage to just storing the blank tiles?  If my maths are correct, 35,000,000 300byte tiles would be 143,360,000,000 bytes on disc (assuming 4096 byte clusters).  Divide by 1024 and 1024 and 1024 to get GB and I get 133.51GB.  That doesn't seem like it would be impossible to do.

Of course, my math could be totally and completely wrong.

-Jeremy

Original Message -----------------------
On Sat, Dec 22, 2007 at 11:10:03AM -0500, Milenko wrote:
> Pardon my ignorance, but what is the purpose of this database of blank 
> tiles?  I'm just curious, as I know little to nothing about what the t at h 
> server does and how it does it.  Is there a wiki page anywhere that 
> explains how the infrastructure works?

Rather than storing millions of 300 byte blank images, any time a blank
image is encountered, it stores a row in a table saying 'this tile is
blank (sea|land)'. At request time, if no tiles exist on disk, the tile
is looked up in the database, and if the tile in the database is there,
an appropriately colored blank image is returned instead.

Regards,
-- 
Christopher Schmidt
MetaCarta