reliable disk FAILURE

when doing a disk-to-disk backup using dump/restore, I reliably get a disk
failure.  I don't think it's the disk because it happens on six different
machines.  All six machines are using SATA drives.  They all have an ASUS
P4P800 MB.

None of the six machines had any problems until after the last security
patch to 5.2.1.  After the patch, they all fail.  If I remember correctly,
the last security patch only touched some TCP files, so the disk failures
don't make any sense to me.

commands causing the failure, console output and dmesg are below.  This is
on a test machine that I can take down or modify at any time, so if there is
anything further that I can do to help debug this - please let me know.

sequence of commands issued to cause failure
----------------------------------------------
Executing command: /bin/dd if=/dev/zero of=/dev/ad14 bs=1k count=1
Executing command: /sbin/fdisk -BI ad14
Executing command: /sbin/bsdlabel -w -B ad14s1 auto
Executing command: /sbin/bsdlabel ad14s1 > /tmp/backup.disk.label
Executing command: /bin/echo 'a: 2097152 0 4.2BSD' >> /tmp/backup.disk.label
Executing command: /bin/echo 'b: 4194304 * swap' >> /tmp/backup.disk.label
Executing command: /bin/echo 'd: 125829120 * 4.2BSD' >>
/tmp/backup.disk.label
Executing command: /bin/echo 'e: * * 4.2BSD' >> /tmp/backup.disk.label
Executing command: /sbin/bsdlabel -R -B ad14s1 /tmp/backup.disk.label
Executing command: /sbin/newfs -U /dev/ad14s1a
Executing command: /sbin/newfs -U /dev/ad14s1d
Executing command: /sbin/newfs -U /dev/ad14s1e
Executing command: /sbin/mount -rw /dev/ad14s1a /mnt
Executing command: /sbin/dump -0Lf - / | (cd /mnt; /sbin/restore -rf -)
Executing command: /sbin/umount /mnt
Executing command: /sbin/mount -rw /dev/ad14s1d /mnt
Executing command: /sbin/dump -0Lf - /usr | (cd /mnt; /sbin/restore -rf -)
  DUMP: Date of this level 0 dump: Mon Mar 15 10:32:02 2004
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping snapshot of /dev/ad12s1d (/usr) to standard output
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 1621128 tape blocks.
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
warning: ./.snap: File exists
(dump/restore dies here - this time (doesn't die in same place every time) -
causing the following output on the console)


console output
---------------
ad12: TIMEOUT - READ_DMA retrying (2 retries left) LBA=28166139
ad12: timeout sending command=c8
ad12: error issuing DMA command
GEOM: create disk ad12 dp=0xc6ded160
ad12: 76319MB <ST380013AS> [155061/16/63] at ata6-master UDMA100
ad12: FAILURE - SETFEATURES SET TRANSFER MODE timed out

dmesg
------
Copyright (c) 1992-2004 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD 5.2.1-RELEASE-p1 #5: Fri Mar  5 17:54:52 MST 2004
    root_at_oregon.etv.net:/usr/obj/usr/src/sys/GENERIC
Preloaded elf kernel "/boot/kernel/kernel" at 0xc0a35000.
Preloaded elf module "/boot/kernel/acpi.ko" at 0xc0a3521c.
ACPI APIC Table: <A M I  OEMAPIC >
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Pentium(R) 4 CPU 2.60GHz (2598.76-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf29  Stepping = 9

Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA
,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Hyperthreading: 2 logical CPUs
real memory  = 1072889856 (1023 MB)
avail memory = 1032749056 (984 MB)
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
ioapic0 <Version 2.0> irqs 0-23 on motherboard
Pentium Pro MTRR support enabled
npx0: [FAST]
npx0: <math processor> on motherboard
npx0: INT 16 interface
acpi0: <A M I  OEMXSDT > on motherboard
pcibios: BIOS version 2.10
Using $PIR table, 14 entries at 0xc00f5410
acpi0: Power Button (fixed)
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
acpi_cpu0: <CPU> on acpi0
acpi_cpu1: <CPU> on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
agp0: <Intel 82865 host to AGP bridge> mem 0xf8000000-0xfbffffff at device
0.0 on pci0
pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0
pcib1: could not get PCI interrupt routing table for \\_SB_.PCI0.P0P1 -
AE_NOT_FOUND
pci1: <ACPI PCI bus> on pcib1
pci1: <display, VGA> at device 0.0 (no driver attached)
uhci0: <Intel 82801EB (ICH5) USB controller USB-A> port 0xef00-0xef1f irq 16
at device 29.0 on pci0
usb0: <Intel 82801EB (ICH5) USB controller USB-A> on uhci0
usb0: USB revision 1.0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
uhci1: <Intel 82801EB (ICH5) USB controller USB-B> port 0xef20-0xef3f irq 19
at device 29.1 on pci0
usb1: <Intel 82801EB (ICH5) USB controller USB-B> on uhci1
usb1: USB revision 1.0
uhub1: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 2 ports with 2 removable, self powered
uhci2: <Intel 82801EB (ICH5) USB controller USB-C> port 0xef40-0xef5f irq 18
at device 29.2 on pci0
usb2: <Intel 82801EB (ICH5) USB controller USB-C> on uhci2
usb2: USB revision 1.0
uhub2: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub2: 2 ports with 2 removable, self powered
uhci3: <Intel 82801EB (ICH5) USB controller USB-D> port 0xef80-0xef9f irq 16
at device 29.3 on pci0
usb3: <Intel 82801EB (ICH5) USB controller USB-D> on uhci3
usb3: USB revision 1.0
uhub3: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub3: 2 ports with 2 removable, self powered
pci0: <serial bus, USB> at device 29.7 (no driver attached)
pcib2: <ACPI PCI-PCI bridge> at device 30.0 on pci0
pci2: <ACPI PCI bus> on pcib2
skc0: <3Com 3C940 Gigabit Ethernet> port 0xd800-0xd8ff mem
0xfeafc000-0xfeafffff irq 22 at device 5.0 on pci2
skc0: 3Com Gigabit LOM (3C940)
sk0: <Marvell Semiconductor, Inc. Yukon> on skc0
sk0: Ethernet address: 00:0c:6e:54:4b:25
miibus0: <MII bus> on sk0
e1000phy0: <Marvell 88E1000 Gigabit PHY> on miibus0
e1000phy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseTX-FDX,
auto
atapci0: <Promise PDC20319 SATA150 controller> port
0xdc00-0xdc7f,0xdfa0-0xdfaf,0xdf00-0xdf3f mem
0xfeac0000-0xfeadffff,0xfeafb000-0xfeafbfff irq 21 at device 9.0 on pci2
atapci0: [MPSAFE]
ata2: at 0xfeafb000 on atapci0
ata2: [MPSAFE]
ata3: at 0xfeafb000 on atapci0
ata3: [MPSAFE]
ata4: at 0xfeafb000 on atapci0
ata4: [MPSAFE]
ata5: at 0xfeafb000 on atapci0
ata5: [MPSAFE]
fxp0: <Intel 82550 Pro/100 Ethernet> port 0xde80-0xdebf mem
0xfeaa0000-0xfeabffff,0xfeafa000-0xfeafafff irq 23 at device 11.0 on pci2
fxp0: Ethernet address 00:02:b3:d1:f7:ad
miibus1: <MII bus> on fxp0
inphy0: <i82555 10/100 media interface> on miibus1
inphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
isab0: <PCI-ISA bridge> at device 31.0 on pci0
isa0: <ISA bus> on isab0
atapci1: <Intel ICH5 UDMA100 controller> port
0xfc00-0xfc0f,0-0x3,0-0x7,0-0x3,0-0x7 at device 31.1 on pci0
ata0: at 0x1f0 irq 14 on atapci1
ata0: [MPSAFE]
ata1: at 0x170 irq 15 on atapci1
ata1: [MPSAFE]
atapci2: <Intel ICH5 SATA150 controller> port
0xef60-0xef6f,0xefa8-0xefab,0xefa0-0xefa7,0xefac-0xefaf,0xefe0-0xefe7 irq 18
at device 31.2 on pci0
atapci2: [MPSAFE]
ata6: at 0xefe0 on atapci2
ata6: [MPSAFE]
ata7: at 0xefa0 on atapci2
ata7: [MPSAFE]
pci0: <serial bus, SMBus> at device 31.3 (no driver attached)
pci0: <multimedia, audio> at device 31.5 (no driver attached)
acpi_button0: <Power Button> on acpi0
atkbdc0: <Keyboard controller (i8042)> port 0x64,0x60 irq 1 on acpi0
atkbd0: <AT Keyboard> flags 0x1 irq 1 on atkbdc0
kbd0 at atkbd0
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: model IntelliMouse, device ID 3
sio0 port 0x3f8-0x3ff irq 4 on acpi0
sio0: type 16550A
sio1 port 0x2e8-0x2ef irq 3 on acpi0
sio1: type 16550A
ppc0 port 0x378-0x37f irq 7 on acpi0
ppc0: Generic chipset (NIBBLE-only) in COMPATIBLE mode
ppbus0: <Parallel port bus> on ppc0
plip0: <PLIP network interface> on ppbus0
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ppi0: <Parallel I/O> on ppbus0
orm0: <Option ROMs> at iomem 0xc8000-0xc97ff,0xc0000-0xc7fff on isa0
pmtimer0 on isa0
fdc0: ready for input in output
fdc0: cmd 3 failed at out byte 1 of 3
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
Timecounters tick every 10.000 msec
acd0: CDROM <FX54++M> at ata0-master PIO4
GEOM: create disk ad12 dp=0xc6b91060
ad12: 76319MB <ST380013AS> [155061/16/63] at ata6-master UDMA100
GEOM: create disk ad14 dp=0xc69d1d60
ad14: 76319MB <ST380013AS> [155061/16/63] at ata7-master UDMA100
SMP: AP CPU #1 Launched!
Mounting root from ufs:/dev/ad12s1a
WARNING: / was not properly dismounted
WARNING: /usr was not properly dismounted
WARNING: /var was not properly dismounted