Re: RFC: ATA to CAM integration patch

On Jun 27, 2009, at 7:17 PM, Daniel O'Connor wrote:

> On Sat, 27 Jun 2009, Kamigishi Rei wrote:
>> Hello, hope you're having a nice day,
>>
>> Ulrich Spörlein wrote:
>>> I, personally, think this is not very good idea. People are used to
>>> CAM-devices getting enumerated as da0, da1, etc. All the
>>> documentation talks about ad0 for ATA and da0 (plus camcontrol) for
>>> SCSI, USB, Firewire devices. We also have fd0 and cd0 and should
>>> stick to two-letter-plus-number codes. So either make them all ad0
>>> or da0. I'd vote for the latter, as that is what Linux is doing
>>> (more or less) and people are already familiar with USB drives or
>>> new SATA drives showing up as "SCSI drives, so they get the SCSI
>>> names".
>>
>> This poses the question of daXX enumeration order. I've already had
>> some 'fun' with an IBM server which has an LVD/320 SCSI controller.
>> While the controller's bus was enumerated properly, somehow if you
>> attach an USB mass storage device before the system boot that said
>> mass storage could suddenly appear earlier than one of the SCSI disks
>> (that was on 7.0-RELEASE) thus breaking the boot process sometimes
>> (when it appeared as da0).
>
> 7.2 has UFSID in GENERIC so you can mount your disks that way which is
> non-ambiguous.
>
> Unfortunately you can't specify swap this way because it has no ID, I
> don't know how hard it would be to add such a thing (which would
> require a mkswap or somesuch, and modification to the dump & swap
> code..)
>

I use glabel to create containers with named labels that I then
reference as swap devices.  (e.g., /dev/label/swap0, etc.)

# swapinfo
Device          1024-blocks     Used    Avail Capacity
/dev/label/swap2     1044192        0  1044192     0%
/dev/label/swap3     1044192        0  1044192     0%
/dev/label/swap4     1044192        0  1044192     0%
Total               3132576        0  3132576     0%

louie