very large tile index

[Christopher Condit]

I've got a fairly large set of .tif files (A total of 2774 images at
roughly 400mgs each). They've all had gdaladdo run (at 2 4 8 16), and
then a tile index created. If I attempt to draw the map with mapserver
at the full extents, the cgi request times out. I realize this is too
much data, but the question is: how do I find out at what point the tile
index will break down and overview should be used? Also, if MapServer
won't draw the composite image, will shp2image work?
This is running on a linux machine with 4 2.8 ghz Pentiums and 4gb
RAM...

Thanks,

Chris Condit
condit at sdsc.edu
San Diego Supercomputer Center
9500 Gilman Drive
La Jolla, CA 92093-0505