You are probably reading this post because you have experienced the pain yourself and I dont want to waste anymore of your time and get right to the steps involved in breaking up a huge database or a datafile
Check the space situation on your host
Get the space usage by files for the big database/datafile in question
Decide on number of files to add/location
Add multiple secondary datafiles
Distribute data from big datafile into the new datafiles using EMPTYFILE option
Shrink the big datafile and set a maximum size
Change the default filegroup
Read on for Jana’s step-by-step approach.