I am trying to mosaic seven dem files together by using "mosaic to new raster". The largest one is about 100 GB, and the other six files are total 50 GB. I used "FIRST" mosaic method and the cell size is the same with the largest dem. And the boundary after mosaicing will not change, which is also the same with the largest one. So basiclly the output file should be about 150 GB or 200 GB something like that.
The mosaic work has taken a really long time, which is about 16 hrs and haven't finished yet. I checked the output folder and find there was only two files has been created, total 1.13 TB, which is unreasonable, because it is much larger than I expect. I am thinking if there is some temporary file there caused this and if the long time is reasonable for 100 GB DEM mosaic with 50 GB DEM?