Found another article which mentioned:
"ONTAP is already as optimized as possible for deleting files. So much so that we have a bug where, when there are a very large number of files or very large files being deleted, it takes up all the processing time and other processes are put on hold until the deletes finish, causing the filer to appear unresponsive. See http://now.netapp.com/NOW/products/csb/csb0803-03.shtml"
Is there a fix or settings change I can make so that other users can still read/write small files when large delete jobs are running?