Hi,

so _WHY_ does Oracle not support the crossover cable?

See Metalink Note 220970.1:

The requirement is to use a switch:

Detailed Reasons:
1) cross-cabling limits the expansion of RAC to two nodes
2) cross-cabling is unstable:
 a) Some NIC cards do not work properly with it.
 b) Instability. We have seen different problems e.g.. ORA-29740 at configurations using crossover cable, and other errors.

Due to the benefits and stability provided by a switch, and their afforability, this is the only supported configuration.


Clemens

--- Originalnachricht ---
>
> I do not see serious obstacle here - it is all transparent for
> Oracle. In
> addition, this information is PRETTY OLD - Oracle DO SUPPORT
> RAC on OCFSv2,
> for example; and guess what happen if you build RAC on 10Gbit
> ethernet. I
> should not take this document too seriously. So, it is not an
> answer -
> question was _WHY_, not _WHAT_.
>
> As I know, problem with inetrconection comes from port status
> - RAC cannot
> recognize if port is down because
> interface failure happen (so it must fence itself) OR because
> remote node
> died. Plus, it is not obvious how flow control and port
> negotiation works
> with cross cable and 2 nameles ethernet cards (for example).
> But I run RAC on interconnection without any visible problems,
> so looks as
> they fixed this.
>
> (Adding interconnection switch over-complicated the whole
> system in case of
> 2-node cluster and adds one more porint of instability,
> so it is better to have an option with direct cross-connection.)
>
>
>
> ----- Original Message -----
> From: "Fahrenfort, Keith (PSS Americas Oracle)"
> <keith.fahrenfort@(protected)>
> To: "Alexei_Roudnev" <Alexei_Roudnev@(protected)>
> Cc: <suse-oracle@(protected)>
> Sent: Thursday, February 23, 2006 1:25 PM
> Subject: RE: [suse-oracle] RAC, cluster interconnect and
> essential ports
>
>
> Hi, see first note here -
> http://www.oracle.com/technology/products/database/clustering/certify/te
> ch_generic_linux.html
>
> So as long as you need Oracle support for a Production-level
> system, you
> need to adhere to the above. Or you may be on your own....
>
> Hope this helps!
>  _____
>
> Please let me know if you prefer to not receive email from
> me.
>
> Keith Fahrenfort
> Solutions Architect - Hewlett Packard
> Oracle Solution Design Consulting
> HP Americas Presales Shared Services
> 20555 SH249, MS HOM7
> Houston, TX 77070
> 281.927.8611 - Direct Phone
> 1.800.424.0993 option2 - SDC Team
> keith.fahrenfort@(protected)
> http://www.hp.com/go/oracle
> For HP's privacy policy and contact information, please see
> here -
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>  _____
>
>
> -----Original Message-----
> From: Alexei_Roudnev [mailto:Alexei_Roudnev@(protected)]
> Sent: Thursday, February 23, 2006 1:14 PM
> To: Silviu Marin-Caea; suse-oracle@(protected)
> Subject: Re: [suse-oracle] RAC, cluster interconnect and
> essential ports
>
> Btw, why you don't recommend crossover cables? They work fine,
> and the
> only problem is with port status (if node-1 went down,
> interconnect port
> on
> node-2 went down as well) - but if you, for example, maintain
> 1 link
> thur switch and 4 crosscablem it wil not be a problem (in
> theory).
>
> (You == Oracle, in my question).
>
>
>
> ----- Original Message -----
> From: "Silviu Marin-Caea" <silviu_marin-caea@(protected)>
> To: <suse-oracle@(protected)>
> Sent: Thursday, February 23, 2006 12:23 AM
> Subject: Re: [suse-oracle] RAC, cluster interconnect and
> essential ports
>
>
> > On Thursday 23 February 2006 09:26, Magni Fabrizio wrote:
> > > In my opinion a firewall on the interconnect is a bad idea... And
> not
> > > really necessary since that connection should be on a dedicated
> network
> > > (only for your cluster nodes).
> >
> > Exactly.
> >
> > For interconnect get a 5 port Gigabit switch, like Linksys SD2005
> ($100).
> >
> > Don't use it for anything else.
> >
> > Don't use crossover cable, it not good at all for RAC.
> >
> > So, there is no need for firewall on the interconnect private
> interfaces.
> >
> >
> > --
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> > Please see http://www.suse.com/oracle/ before posting
> >
> >
>
>
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