ada disk now da disk in upgrade to 10.2 Release?

John Howie john at
Fri Aug 14 21:37:35 UTC 2015

root at freebsd:~ # camcontrol devlist
<Msft Virtual CD/ROM 1.0>          at scbus0 target 0 lun 0 (pass0,cd0)
<Msft Virtual Disk 1.0>            at scbus1 target 0 lun 0 (da0,pass1)
root at freebsd:~ # 

No atacontrol :-)

On 8/14/15, 1:51 PM, "Polytropon" <freebsd at> wrote:

>On Fri, 14 Aug 2015 20:14:35 +0000, John Howie wrote:
>> Hi all,
>> I ran an upgrade via freebsd-update from 10.1-RELEASE to 10.2-RELEASE.
>> Everything went well until the reboot after kernel updates. The kernel
>> complained it could not find the root filesystem, which was at
>> /dev/ada0p2. The disk no longer appears in /dev, and it is now
>> /dev/da0p2.
>> The machine is running under Hyper V (a guest OS).
>> Does anyone have any idea why this might have happened?
>This looks like either "Hyper-V" stopped representing the
>disk device as an AHCI device (ada driver: "ATA Direct Access
>device driver"), and the OS now recognizes it as a SCSI
>device (da driver: "SCSI Direct Access device driver"),
>or the OS doesn't contain or load the ada driver for some
>reason, which would be strange, given that the driver is
>part of the GENERIC kernel for some time now. SATA drives
>are commonly recognized by the AHCI driver, PATA drives
>by the default ATA driver (ad driver: "generic ATA/ATAPI
>disk controller driver", considered obsolete now), and
>all other SCSI peripherials use the SCSI drivers. This
>should be the same between 10.1 and 10.2.
>What do "camcontrol devlist" and "atacontrol list" day
>about the recognized disks?
>Magdeburg, Germany
>Happy FreeBSD user since 4.0
>Andra moi ennepe, Mousa, ...

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