ada disk now da disk in upgrade to 10.2 Release?

John Howie john at
Sun Aug 16 17:51:12 UTC 2015

Hi all,

Following up.

I verified that no changes have been made to the HyperV Cluster, and that no changes were made to /etc/fstab in the upgrade. The virtual machine (10.1-RELEASE) was installed on the HyperV Cluster from 10.1-RELEASE media, which created the ada disks and partitions (I do remember there being difficulty in setting the boot partition as active, and having to mark it manually).




On 8/14/15, 2:37 PM, "owner-freebsd-questions at on behalf of John Howie" <owner-freebsd-questions at on behalf of john at> wrote:

>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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