I have hundreds of tifs I want to use as a data store on my Geoserver. So many that QGIS won't merge them for me. I heard some about .vrt but I never found a clear source of information on the matter. What would be the best route to get all of my tif files to behave as a single layer in Geoserver?
Sounds like you'd want to use the image mosaic plugin: http://docs.geoserver.org/stable/en/user/data/raster/imagemosaic/index.html
The configuration of the mosaic can be scary, but if all you want is to merge all the images together visually, then put them in a directory and just point the GeoServer image mosaic at it with no other setups, it should self-configure.