Messages in this thread | | | Date | Thu, 16 Jul 2009 10:23:45 -0700 (PDT) | From | david@lang ... | Subject | Re: deterministic scsi order with async scan |
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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 > >
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