Hi Jan,

On 02/11/10 00:43, Jan Damborsky wrote:
> On 02/11/10 01:43 AM, Shidokht Yadegari wrote:
>> On 02/10/10 03:57, Jan Damborsky wrote:
...

>>
>>>
>>> Is there an easy and stable way to determine if particular disk
>>> is handled by cmkd, i.e. that it should be equipped with ALT slice ?
>>
>> In response to a DKIOCINFO, cmdk/dadk (and pv_cmdk)
>> advertise the disk with  DKC_DIRECT in dki_ctype. And btw so
>> does the dad driver for sparc.
>
> Thanks ! If I understand correctly, we could check for something
> like
>
> if (dki_ctype == DKC_DIRECT) AND (platform != sparc)
>
> Might it be correct ?
Yes or you can have it inside an ifdef.

...

>
>>>
>>>>
>>>> The only time that one may have a problem is on disks where
>>>> opensolaris previously did not include an ALT slice and we are
>>>> now preserving other slices on that disk which occupy the same
>>>> space as where alt slice would have.
>>>
>>>
>>> That leads me to more generic question - what should installer do if 
>>> there
>>> is no space to create ALT slice (e.g. cylinder 1-2 are already 
>>> occupied) ?
>>
>> I am not sure. I am assuming the installer currently allows preserving
>> VTOC slice information on the disk, and that is when we will run into 
>> this problem,
>> right?
>
> Yes. One example when I think we might run into this scenario is
> when SATA drive is being used in machine where SATA controller is
> handled by new SATA framework and then that disk is put into another
> machine for purposes of the installation where SATA controller is
> handled by cmdk and installer is asked to install into existing slice
> (no VTOC changes).
> Since format allows to manipulate disk without ALT slice (it just
> displays warning that No ALT slice was found),
> I am wondering if we might do the same in the installer - if cylinders
> 1-2 are already occupied and thus there is no space to create ALT slice
> (assuming here that we are not allowed to pick arbitrary starting 
> cylinder),
> installer would just log warning message and proceed with the 
> installation.


Sounds reasonable to me.
>
>>>
>>>
>>>>
>>>>>
>>>>> Also, as you indicated, the concept of alternate slice on
>>>>> drives handled by cmdk device driver in Solaris seems to be
>>>>> outdated and from longer term point of view it is something
>>>>> which might be removed - as it was done for SCSI or SATA drives
>>>>> handled by new SATA framework.
>>>>> Do you think that it might be reasonable to continue with
>>>>> that longer term effort ?
>>>> Imho yes. It reduces complexity and it is a feature
>>>> that I have not seen used in many many years.
>>>
>>> Based on this, what you might recommend as a reasonable way
>>> to proceed with this effort ? Might it be sufficient to file bug
>>> for this issue or more steps might be needed ?
>> Of course whoever will take responsibility of the RFE to EOL 
>> addbadsec and friends,
>> would need to take it to PSARC and think about any potential 
>> backwards compatibility
>> issues, etc. I am not sure what you are asking here.
>
> That is what I was not sure about - thank you for clarifying this.
> Do you happen to know what might appropriate bug category
> for filing this RFE ?
solaris/utility/diskformat sounds good to me.

The fix will require changes to  cmdk, cmlb, pv_cmdk, format, addbadsec, 
header files,...
(and installer ;-))


best regards,
--shidokht
>
> Thank you very much,
> Jan
>

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