Re: Oracle Parallel Server and 24x7 availability

In article <960305947.21689.0.nnrp-09.9e984b29_at_news.demon.co.uk>,   "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote:
>
> You are thinking of 'cache fusion'.
> This is a feature to reduce pinging due
> to read/write contention, not write/write.
>
> Oracle has implemented a 'consistent read
> server', so that if node A want to read a block
> that has recently been updated (and not written)
> by node B then node B will create a consistent
> read image of that block and pass it down the
> interconnect rather than writing the block, and
> the associated rollback segment header and
> rollback blocks that node A would need to
> create a CR image for itself.
>
> It node A want to write to the block, node B
> still has to ping it down.
>
> --
>
> Jonathan Lewis
> Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
>

Jonathan --

I think Bob was referring to a new 8.1.6 configuration option of OPS for high availability...

This is known as "Basic High Availability Configuration" or "Primary and Secondary Instances". See

http://technet.oracle.com/doc/oracle8i_816/paraserv.816/a76968/pshavdtl. htm#10876

and

http://technet.oracle.com/doc/oracle8i_816/paraserv.816/a76934/chap5.htm #1023930

for more info.

It optimizes OPS to run in a 2 node environment where one node "reads" and the other "reads and writes" and further reduces pinging/inter node issues...

It doesn't necessarily add to scaling in this configuration, only availability.

(welcome back, haven't seen you on the group for a while...)

> Bob Fazio wrote in message
> <_C8_4.231578$Tn4.2063175_at_news1.rdc2.pa.home.com>...
> >This will be short and sweet.
> >
> >I use it. I like it. I would recommend it. Raw devices aren't that
 hard,
> >infact I prefer them. It's not what is advertised, but it's still
 worth
 it.
> >In oltp enviroments you will want to be cautious, although I read
 that
 8.1.6
> >does have mode that eliminates the problem with pinging that can
 occur in
> >oltp enviroments.
> >
>
>

--
Thomas Kyte (tkyte_at_us.oracle.com) Oracle Service Industries
Howtos and such: http://osi.oracle.com/~tkyte/index.html
Oracle Magazine: http://www.oracle.com/oramag
Opinions are mine and do not necessarily reflect those of Oracle Corp


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