I can't get an Ultrium-2 LTO drive to stream, and (I think) I've traced the problem to the read performance of the USB2-attached NTFS disk, and specifically the NTFS filesystem. I'm reading a single 190GB file, and the throughput I'm getting is 5.4MB/s: $ dd if=ad2c.dump of=/dev/null bs=1M ^? load: 0.04 cmd: dd 1434 [biord] 0.00u 4.78s 2% 1672k 610+0 records in 610+0 records out 639631360 bytes transferred in 117.937613 secs (5423472 bytes/sec) The is an old but relatively fast machine CPU: Intel(R) Pentium(R) 4 CPU 2.40GHz (2407.18-MHz 686-class CPU) running 7.0-RC1: $ uname -a FreeBSD icarian.dmst.aueb.gr 7.0-RC1 FreeBSD 7.0-RC1 #0: Mon Dec 24 12:18:24 UTC 2007 root@logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC i386 and the load during the read remains comfortably low: $ uptime 6:34PM up 3:50, 3 users, load averages: 0.09, 0.04, 0.04 Reading from the raw device tripples the performance: # dd if=/dev/da0s1 bs=1m of=/dev/null 533725184 bytes transferred in 34.777460 secs (15346871 bytes/sec) bringing it on par with what I get from Windows (on a different machine): F:\>dd if=other.20051007.tgz of=/dev/null bs=1M 1231030919 bytes (1.2 GB) copied, 82.845 s, 14.9 MB/s These are some (vaguely) relevant parts of dmesg: ehci0: [GIANT-LOCKED] ehci0: [ITHREAD] usb2: EHCI version 0.95 usb2: companion controllers, 3 ports each: usb0 usb1 usb2: <NEC uPD 720100 USB 2.0 controller> on ehci0 usb2: USB revision 2.0 uhub2: <NEC EHCI root hub, class 9/0, rev 2.00/1.00, addr 1> on usb2 uhub2: 5 ports with 5 removable, self powered [...] ad0: 76319MB <WDC WD800JB-00CRA1 17.07W17> at ata0-master UDMA100 acd0: DVDROM <DVD-ROM BDV316C/VER .20R> at ata1-master UDMA33 acd1: DVDR <SONY DVD RW DW-U10A/1.1d> at ata1-slave UDMA33 da0 at umass-sim0 bus 0 target 0 lun 0 da0: <WDC WD32 00JB-00KFA0 \\0000\\0000> Fixed Direct Access SCSI-0 device da0: 40.000MB/s transfers da0: 305245MB (625142448 512 byte sectors: 255H 63S/T 38913C) GEOM_LABEL: Label for provider da0s1 is ntfs/Backup. Trying to mount root from ufs:/dev/ad0s2a GEOM_LABEL: Label ntfs/Backup removed. GEOM_LABEL: Label for provider da0s1 is ntfs/Backup. I'd appreciate any suggestions you may have. Diomidis Spinellis - http://www.spinellis.gr