iSCSI LUN number in Celerra should correspond to Disk # in Disk Management. You can also try the inq utility  ftp://ftp.emc.com/pub/symm3000/inquiry/v7.3.2.0/inq.exe_wnt  inq.exe_wnt -celerra
I am tearing down an old backup server with several iscsi volumes.  Is there a way to tie a volume or drive serial back to the Celerra?  I'm not sure how to identify exactly what I am removing from the server.  Windows Server 2003 FWIW
How to indentify windows drive to celerra LUN