When installing a Distribution Point (DP) during ConfigMgr installation, it will be placed on the disk with the most free diskspace. When you install it afterwards a selection of disks can be choosed. Even better is to place a NO_SMS_ON_DRIVE.SMS file on all drives where you don't want a DP. They will be excluded next time.
When the DP is already installed on the wrong drive or when it must be moved to another location, ContentLibraryTransfer.exe can be used.
ContentLibraryTransfer.exe is a tool that will move a distribution point’s content store from one drive to another. That's it, and it is a very simple process.
The syntax used with the tool is – ContentLibraryTransfer.exe –SourceDrive <Current Drive Letter> -TargetDrive <New Drive Letter>
The ContentLibraryTransfer.exe respects NO_SMS_ON_DRIVE.SMS files. In other words if the drive specified as the TargetDrive contains a NO_SMS_ON_DRIVE.SMS the ContentLibraryTransfer.exe will not copy the content library to this drive.
More information on this can be found on MS TechNet.