Re: Device-mapper-multipath RDAC

[Chandra Seetharaman <sekharan@us.ibm.com>]

On Tue, 2007-09-25 at 08:52 +0100, Nuno Fernandes wrote:
> On Tuesday 25 September 2007 06:54:39 Hannes Reinecke wrote:
> > Nuno Fernandes wrote:
> > > hello,
> > >
> > > Just a question:
> > >
> > > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > > configuration should be in storage DS4700? AVT (Automatic Volume
> > > transfer) turned on or off?
> >
> > Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
> > to transfer the volumes from one controller to the other automatically.
> >
> > > When it's turned on, luns keep on jumping from controller to controller..
> >
> > Indeed. That's to be expected.
> >
> > As a rule:
> >
> > - With rdac hardware handler: AVT off
> I'm in the process of testing avt in the kernel.
> 
> > - Without hardware handler: AVT on
> With this situation i don't have any point of failure but the lun keeps on 
> jumping (because of the alive path check of multipathd) and the performance 
> is awfull.

Hmm... Did you have the configuration entries in multipath.conf (same as
that of the RDAC case - with the exception of the hardware handler) ?
> 
> Best regards
> Nuno Fernandes
> 
> >
> > Cheers,
> >
> > Hannes
> 
> 
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-- 

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    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
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