Re: add node , oracle software a bit error

In the scenarios involving larger numbers of nodes, I would advocate *some* 
sharing of OHs, but never a single OH for the whole cluster. In discussions 
with some of the engineers at Oracle, there was talk of a whitepaper to 
describe the optimal or best practice in the area of shared OHs, but I don't 
think it ever got published. 

I agree with your first point for shared homes--you do guarantee that the same 
patches are used by all nodes sharing that OH. However, I submit that I could 
guarantee the same with careful administration practices and still benefit from 
all the non-shared OH points you made (which are all good ones). I'd offer a 
clarification on the last point about rolling patches. You said that it is 
easier to apply rolling patches--I think you mean to say that it is *possible* 
to apply rolling patches with non-shared OHs. I suppose that you could apply 
rolling patches with a shared home, but, at least for part of the process, you 
don't have a shared OH.

So, I still haven't found a compelling reason to use shared OHs. I'm all eyes 
for anyone that can make the good case for it.

Dan

----- Original Message ----
From: Alex Gorbachev <ag@xxxxxxxxxxxx>
To: Dan Norris <dannorris@xxxxxxxxxxxxx>
Cc: randyjo@xxxxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Sent: Tuesday, July 10, 2007 4:39:33 PM
Subject: Re: add node , oracle software a bit error

I will list some pros and cons - if anyone feels like adding some more
- by all means, please do.

With shared Oracle home
- You are guaranteed to have the same patches on both nodes and use
actually the same binaries.
- It's supposedly easier to manage (was a disaster in 9i though)
especially on large RAC installations (by number of nodes).

I'm a bit skeptical as it requires some CFS or NFS to manage and it's
yet another software stack if you are not using it as your primary
database storage as well.

My arguments for non-shared homes:
- local filesystem is way simpler and rock solid.
- if you screwed up something on one node - it is not propagated on
another node (have you had someone wiping out the oracle homes
completely? One SA sis that clean up for me once).
- it's easier to apply rolling patches. Otherwise, for shared home it
would require new home installation and re-register databases and
instances. In the end, I'm actually not sure if that will be "online"
in the end.

Just my two cents.

Cheers,
Alex

On 7/10/07, Dan Norris <dannorris@xxxxxxxxxxxxx> wrote:
>
> FWIW, I'm in the same boat--"it depends", but I have very rarely heard
> compelling arguments for using a shared OH. I just talked with another
> customer this morning that is very much looking forward to their 9i->10g RAC
> upgrade/migration so that they can eliminate the shared OH from their
> environment.
>
> Dan
>
> ----- Original Message ----
> From: Alex Gorbachev <ag@xxxxxxxxxxxx>
> To: randyjo@xxxxxxxxxxxxx
> Cc: oracle-l@xxxxxxxxxxxxx
> Sent: Tuesday, July 10, 2007 1:51:57 PM
> Subject: Re: add node , oracle software a bit error
>
>
> Well, there are two groups - some believe that shared oracle homes are
> better from manageability and reliability and others prefer non-shared
> installations.
>
> Both have their arguments and there is a third group that would say
> "it depends". I probably belong to the third group but lean more
> towards non-shared homes as a more reliable option.
>
> On 7/10/07, Randy Johnson <randyjo@xxxxxxxxxxxxx> wrote:
> > Good tip on the shared filesystem for the oraInventory. Sharing the
> > oraInventory across nodes is not a good practice in my opinion. It runs
> > counter to the whole concept of redundancy in an HA configuration and RAC
> > was not written to support it.



-- 
Alex Gorbachev, Oracle DBA Brewer, The Pythian Group
http://www.pythian.com/blogs/author/alex http://www.oracloid.com
BAAG party - www.BattleAgainstAnyGuess.com

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