On Jan 31, 2008 5:02 PM, Sharpe, Sam J <[EMAIL PROTECTED]> wrote:

>
> On 31 Jan 2008, at 21:43, dbcooper wrote:
>
> > Domenico,  (and everyone else thanks)
> >
> > Thank you for your input. This seems to be a deeper rabbit hole than
> > I expected.
> >
> > I tried (echo "1" > /sys/bus/scsi/drivers/sd/<SCSI-ID>/delete) and
> > sure enough it cleanly wiped out the /dev/sdc and the /sys/block/
> > device etc.  Upon reboot, it was back and had the same old Buffer I/
> > O errors and block errors on reboot and recreated the same /dev/sdc
> > etc.
> >
> > So I started digging through the udev / udevinfo commands and
> > comparing with lspci to find that yes the ghost /dev/sdc was hanging
> > (supposedly) off my Qlogic Fiber Card, I then launched my Navisphere
> > to make sure it only had one LUN being handed out (and it is). So I
> > got even more confused. I've not got much SAN experince and I was
> > handed this with my servers. I then took a look at the SANSurfer Cli
> > tool (sfcli), I was able to see that the HBA does see (looks like
> > it) 2 LUNS of exaclty the same size (I.E. it's really just the one I
> > guess).
>
> A barrage of questions:
>
> Whose QLogic drivers are you using? Do you have multiple Fibre cards
> in the system? Is your QLogic card dual-port? Do you have multiple SAN
> switches?
>
> This sounds to me very like our systems would look when we have two
> SAN paths to the same LUN (i.e. redundant fibre cards and a redundant
> fabric). Unless you are using QLogic drivers that natively understand
> Multipathing (it's an option - Red Hat's ship without as the preferred
> method is dm-multipath - HPs (just as an example) ship with it turned
> on so you don't need dm-multipath.)
>
> --
> Sam
>
>
> > The LUN that is being presented to the machine is being mounted as
> > sdd. (the offender I'm hunting down is sdc).
> > Do you think it's possible that when I delete the sdc with the above
> > "echo 1" you suggested and reboot, that the kernel is trying to
> > assign the presented LUN as the next device in line sdc? (since sda,
> > sdb and sdd are taken).
> >
> > I don't know anything about the persistent binding (yet) but I'll be
> > going through all the docs from the Qlogic and EMC products tomorrow
> > (now that I know what to start looking at).
> >
> > Thanks for any other advice (if you can suggest any).
> >
>
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Thank you, I'll get back to this tomorrow.
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