Re: Qlogic FC Multipath and engenio

[Michael Loftis <mloftis@modwest.com>]

--On February 1, 2006 2:52:41 PM +0100 Andrew Miehs <andrew@2sheds.de> 
wrote:

> If I access the 'second path' via the 'other' controller to a disk, I
> get io errors...
>
> Is this normal? I was expecting that all controllers offer all disks
> equally, and am
> a bit confused about this 'default active' setting...

Yes and no.  You have to 'trespass' when you activate teh LUN on the 
secondary controller (controller that is not primary for that LUN) and a 
lot of gear, esp low end, can't auto-trespass.  You have to send it either 
a SCSI command (special to each and every storage array, tehre's no 
standard here) or the hosts and/or LUN have to be setup in some special way 
to allow for auto trespassing.  Contact your storage vendor or check your 
documentation for details on how to do this.


> I has hoping to avoid compiling the RDAC driver from engenio as it is
> 'configured'
> for RedHat or Suse, and I now have to go through the Makefile to fix  it
> - hopefully
> this should be pretty easy... Their RDAC driver seems to use 'MPP'  for
> the failover
> - whatever this is.... I guess I will work that out in the next  couple
> of hours!
>
> Thanks for any suggestions,
>
> Andrew
>
>
> On Feb 1, 2006, at 2:39 PM, Doug Griswold wrote:
>
> > You will see at least 2 devices for every one drive depending on
> > your san configuration.  Multipath tools or mdadm can combine these
> > to make one multipath device.   The qlogic driver will do this for
> > you as well.  From what I have seen if you want support from the
> > storage company you should connect the way they specify in their docs.
>
>
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--
Michael Loftis
Modwest Operations Manager
Powerful, Affordable Web Hosting