I have a Windows 2008 R2 file/app server. One night a week, I copy some files to share on a NAS. This is a production server that has active users 24/7. During the time that the files are copying to the NAS, the server becomes almost inaccessible because of the bandwidth across the HP ProCurve Switch. I am thinking of utilizing QoS on the switch but not sure which is the best option. I thought of prioritizing ports first. For that, would I give low priority to SMB ports 137, 138, and 139?