Raise burden put on server (6)
I believe the answer is:
upload
'put on server' is the definition.
'raise burden' is the wordplay.
'raise' becomes 'up' (I've seen this in other clues).
'burden' becomes 'load' ('load' can be a synonym of 'burden').
'up'+'load'='UPLOAD'
(Other definitions for upload that I've seen before include "post on YouTube?" , "Transfer a file from one computer to another" , "Transfer 1 Down" , "Stuff transferred" , "Transfer a file from a smaller to a large computer" .)