Upgrading to 7.1 change my 2nd hard disk name

Today I upgrade one of my servers from 7.0 to 7.1.

After the kernel update I reboot the system and didn't boot up so I ask for KVM over IP and found that the 2nd hard disk name change from /dev/ad6 to /dev/ad8

Someone else experience the same?
Could it be possible that 7.1 recognize an additional onboard disk controller on your mainboard?
Which model do you have?
Here is the output of dmesg:

Copyright (c) 1992-2009 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 is a registered trademark of The FreeBSD Foundation.
FreeBSD 7.1-RELEASE-p2 #0: Sat Jan 24 18:16:37 EET 2009
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 5600+ (2899.98-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x60fb2  Stepping = 2
  AMD Features=0xea500800<SYSCALL,NX,MMX+,FFXSR,RDTSCP,LM,3DNow!+,3DNow!>
  AMD Features2=0x11f<LAHF,CMP,SVM,ExtAPIC,CR8,Prefetch>
  Cores per package: 2
real memory  = 2113732608 (2015 MB)
avail memory = 2058690560 (1963 MB)
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
ioapic0 <Version 2.1> irqs 0-23 on motherboard
kbd1 at kbdmux0
ath_hal: (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
acpi0: <M S I OEMRSDT> on motherboard
acpi0: [ITHREAD]
acpi0: Power Button (fixed)
acpi0: reservation of 0, a0000 (3) failed
acpi0: reservation of 100000, 7df00000 (3) failed
Timecounter "ACPI-safe" frequency 3579545 Hz quality 850
acpi_timer0: <32-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0
pci1: <ACPI PCI bus> on pcib1
vgapci0: <VGA-compatible display> port 0xc000-0xc0ff mem 0xfc000000-0xfdffffff,0xfe9f0000-0xfe9fffff,0xfe800000-0xfe8fffff irq 18 at device 5.0 on pci1
pci1: <multimedia> at device 5.2 (no driver attached)
pcib2: <ACPI PCI-PCI bridge> at device 7.0 on pci0
pci2: <ACPI PCI bus> on pcib2
re0: <RealTek 8168/8168B/8168C/8168CP/8168D/8111B/8111C/8111CP PCIe Gigabit Ethernet> port 0xd800-0xd8ff mem 0xfeaff000-0xfeafffff irq 19 at device 0.0 on pci2
re0: turning off MSI enable bit.
re0: Chip rev. 0x38000000
re0: MAC rev. 0x00000000
miibus0: <MII bus> on re0
rgephy0: <RTL8169S/8110S/8211B media interface> PHY 1 on miibus0
rgephy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 1000baseT-FDX, auto
re0: Ethernet address: 00:21:85:63:74:79
re0: [FILTER]
atapci0: <ATI IXP600 SATA300 controller> port 0xb000-0xb007,0xa000-0xa003,0x9000-0x9007,0x8000-0x8003,0x7000-0x700f mem 0xfe7ff800-0xfe7ffbff irq 22 at device 18.0 on pci0
atapci0: [ITHREAD]
atapci0: AHCI Version 01.10 controller with 4 ports detected
ata2: <ATA channel 0> on atapci0
ata2: [ITHREAD]
ata3: <ATA channel 1> on atapci0
ata3: [ITHREAD]
ata4: <ATA channel 2> on atapci0
ata4: [ITHREAD]
ata5: <ATA channel 3> on atapci0
ata5: [ITHREAD]
ohci0: <OHCI (generic) USB controller> mem 0xfe7fe000-0xfe7fefff irq 16 at device 19.0 on pci0
ohci0: [ITHREAD]
usb0: OHCI version 1.0, legacy support
usb0: SMM does not respond, resetting
usb0: <OHCI (generic) USB controller> on ohci0
usb0: USB revision 1.0
uhub0: <ATI OHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on usb0
uhub0: 2 ports with 2 removable, self powered
ohci1: <OHCI (generic) USB controller> mem 0xfe7fd000-0xfe7fdfff irq 17 at device 19.1 on pci0
ohci1: [ITHREAD]
usb1: OHCI version 1.0, legacy support
usb1: SMM does not respond, resetting
usb1: <OHCI (generic) USB controller> on ohci1
usb1: USB revision 1.0
uhub1: <ATI OHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on usb1
uhub1: 2 ports with 2 removable, self powered
ohci2: <OHCI (generic) USB controller> mem 0xfe7fc000-0xfe7fcfff irq 18 at device 19.2 on pci0
ohci2: [ITHREAD]
usb2: OHCI version 1.0, legacy support
usb2: SMM does not respond, resetting
usb2: <OHCI (generic) USB controller> on ohci2
usb2: USB revision 1.0
uhub2: <ATI OHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on usb2
uhub2: 2 ports with 2 removable, self powered
ohci3: <OHCI (generic) USB controller> mem 0xfe7fb000-0xfe7fbfff irq 17 at device 19.3 on pci0
ohci3: [ITHREAD]
usb3: OHCI version 1.0, legacy support
usb3: SMM does not respond, resetting
usb3: <OHCI (generic) USB controller> on ohci3
usb3: USB revision 1.0
uhub3: <ATI OHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on usb3
uhub3: 2 ports with 2 removable, self powered
ohci4: <OHCI (generic) USB controller> mem 0xfe7fa000-0xfe7fafff irq 18 at device 19.4 on pci0
ohci4: [ITHREAD]
usb4: OHCI version 1.0, legacy support
usb4: SMM does not respond, resetting
usb4: <OHCI (generic) USB controller> on ohci4
usb4: USB revision 1.0
uhub4: <ATI OHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on usb4
uhub4: 2 ports with 2 removable, self powered
ehci0: <EHCI (generic) USB 2.0 controller> mem 0xfe7ff000-0xfe7ff0ff irq 19 at device 19.5 on pci0
ehci0: [ITHREAD]
usb5: EHCI version 1.0
usb5: companion controllers, 2 ports each: usb0 usb1 usb2 usb3 usb4
usb5: <EHCI (generic) USB 2.0 controller> on ehci0
usb5: USB revision 2.0
uhub5: <ATI EHCI root hub, class 9/0, rev 2.00/1.00, addr 1> on usb5
uhub5: 10 ports with 10 removable, self powered
pci0: <serial bus, SMBus> at device 20.0 (no driver attached)
atapci1: <ATI IXP600 UDMA133 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xff00-0xff0f at device 20.1 on pci0
ata0: <ATA channel 0> on atapci1
ata0: [ITHREAD]
isab0: <PCI-ISA bridge> at device 20.3 on pci0
isa0: <ISA bus> on isab0
pcib3: <ACPI PCI-PCI bridge> at device 20.4 on pci0
pci3: <ACPI PCI bus> on pcib3
acpi_button0: <Power Button> on acpi0
sio0: <16550A-compatible COM port> port 0x2f8-0x2ff irq 3 flags 0x10 on acpi0
sio0: type 16550A
sio0: [FILTER]
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
atkbd0: [ITHREAD]
cpu0: <ACPI CPU> on acpi0
acpi_throttle0: <ACPI CPU Throttling> on cpu0
acpi_throttle0: CLK_VAL field overlaps THT_EN bit
device_attach: acpi_throttle0 attach returned 6
powernow0: <PowerNow! K8> on cpu0
cpu1: <ACPI CPU> on acpi0
powernow1: <PowerNow! K8> on cpu1
pmtimer0 on isa0
orm0: <ISA Option ROM> at iomem 0xcd800-0xce7ff pnpid ORM0000 on isa0
ppc0: parallel port not found.
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 1.000 msec
ad4: 381554MB <SAMSUNG HD403LJ CT100-13> at ata2-master SATA300
ad8: 381554MB <SAMSUNG HD403LJ CT100-13> at ata4-master SATA300
SMP: AP CPU #1 Launched!
Trying to mount root from ufs:/dev/ad4s1a
re0: link state changed to UP