Re: Version blues

From: Bob Jones <email_at_me.not>
Date: Thu, 11 Jun 2009 20:07:05 -0500
Message-ID: <PShYl.22280$>

"Serge Rielau" <> wrote in message
> Bob Jones wrote:
>>> Where did I mention shared nothing?
>> GridScale IS a "share nothing" approach. Each instance in the cluster has
>> it's own database.
> Typically people refer to DB2's DPF as shared nothing, but OK. Technically
> xkoto is as "shared nothing" as Dataguard or replication.
> How is that a bad thing?

I did not say that is a bad thing. I am just saying it is different.

>>> The relationship between IBM and xkoto is pretty tight. They are
>>> literally only a subway token away
>> Regardless of how tight the relationship is, GridScale runs outside of
>> DB2 and is licensed separately. They are likely deployed in separate
>> tiers as well.
> How is that a bad thing?

That depends on your definition of "bad thing". To me, complexity is never a good thing.

>>> xKoto basically drives two (or more) replicas of the database.
>>> (similar to a RAC or Dataguard assuming you have true HA on your disk).
>> A single update will need to be applied on each cluster node to keep data
>> in sync. That's more similar to replication not RAC.
> It solves the same business case. Isn't THAT what you woudl define as
> "similar"? If you want DR in RAC you need to 'double up" with Dataguard
> which gets really pricey....

You can say RAC, Replication and Dataguard are all similar. However they do not necessarily solve the same business case or meet the same requirements. Most of all they are architecturally different.

>>> HADR (somewhat similar to Dataguard) gives you HA with few seconds
>>> failover time and near zero extra admin skills needed. That's used for
>>> most SAP systems on DB2.
>> Again, that is not RAC.
> Again why is that bad? It does the job, it's cheap what more can you ask
> for?

Does what job? Does the jobs RAC does.

> What would be a "similar" solution in your world?
> Does a DB2 Sysplex count as similar to RAC?

"Share nothing" is not similar to "share everything". It is just that simple. Received on Thu Jun 11 2009 - 20:07:05 CDT

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