ATA controller and Hyper-V "synthetic storage driver" handle the IDE disks devices ( but not for the CD-ROM) Re: Hyper-V on FreeBSD

Alexander Motin mav at
Tue May 7 08:07:53 UTC 2013

On 07.05.2013 10:40, Victor Miasnikov wrote:
>> prevent default OS driver from attaching to emulated ATA controller
>> when Hyper-V
> Disable both primary and secondary ATA controller prevent use CD-ROM
> device in VM ( guest)
> Because "synthetic storage driver" not handle CD-ROM devices
> ( IMHO, even more: Hyper-V host work with CD-ROM only as "PCI bus" device)

Then may be possibility of blocking/hiding specific ATA channels or 
devices could be investigated.

> ==
> . . .
> On 23.04.2013 17:07, Larry Melia wrote:
> . . .
>> Removing our ATA patches, on the other hand, results in a huge
>> performance loss. This is because the root file system is managed by the
>> ATA driver, which is emulated under Hyper-V.
> ==
> Place on IDE disk only "\boot" ( and bootloader), other on SCSI .

May be instead of splitting filesystem it could be better to boot from 
"SCSI" completely and forget about "ATA"? Or there is no option ROM for 
SCSI boot in Hyper-V?

Alexander Motin

More information about the freebsd-virtualization mailing list