lkml.org 
[lkml]   [2009]   [Jul]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: deterministic scsi order with async scan
On Thu, 16 Jul 2009, Matthew Wilcox wrote:

> On Wed, Jul 15, 2009 at 06:09:22PM -0700, david@lang.hm wrote:
>> is there any way to get deterministic device ordering with scsi async
>> scanning?
>>
>> currently (2.6.30) it seems that the various scsi busses are loaded in
>> the order that they are detected, which can vary from boot to boot
>> depending on how long it takes for the card to initialize.
>
> I think you're confused. The async scsi scanning was designed to _not_
> move devices around randomly. There are other asynchronous schemes in
> the kernel, some of which were not designed with the same care.
>
> The SCSI async scan can't do much about it if the busses are detected
> in a different order.
>
>> would it be possible to detect the cards/drives, but not register them
>> until all the detection is complete so that they can be registered in a
>> deterministic order?
>
> That's exactly how the scsi async scanning works.

hmm, in that case how can I troubleshoot why this system is detecting the
two different PCI-E cards in different orders on different boots.

David Lang

>> having two drives on two different controllers swap positions from boot
>> to boot makes it very painful. yes I can make an initrd that fixes this
>> up in user space by examining each drive and creating links to re-order
>> them, but this is a lot of work to fix randomization that can be
>> prevented in the first place.
>>
>> David Lang
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
>


\
 
 \ /
  Last update: 2009-07-16 19:25    [W:0.382 / U:0.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site