ada disk now da disk in upgrade to 10.2 Release?

Polytropon freebsd at
Fri Aug 14 20:51:13 UTC 2015

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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