Thanks for your replies. According to IBM, 3592 J1A tape drive has Compressed sustained data rate of 80 MB/s and Maximum interface burst transfer rate of 200 MB/s
http://publib.boulder.ibm.com/infocenter/ts3500tl/v1r0/index.jsp?topic=/com.ibm.storage.3584.doc/ipg_3584_a69p0cti20.html When backing up a storage pool (source and destination pools are based on 3592 J1A drives), I noticed that transfer rate between two drives was more than 100MB/s for a long period of time. "q proc" showed that a big file (more than 200GB) was being transferred. Why the transfer rate exceeded 80MB? Many thanks, Mehdi