Re: Oracle RAC for scalability or High Availability only

JEDIDIAH wrote:

> OTOH, adding nodes to the cluster is not just about the cost of
> the boxes or of Oracle. Each box is going to your network and storage
> systems overhead.

No more or less so than any other method of satisfying the same overhead. One can always choose to favour the networks by just limiting the number of users but that is rarely a winning suggestion in a meeting with management.

> That next box might require you to get another high
> speed network switch (or 2 if you are being extra robust). The same goes
> with your fiber switches. Then there's the question of whether or not
> your storage array can handle that level of concurrency (nfs, iscsi or san).

Again no more so than with any other box. 12 CPUs in one box versus 3x4CPU nodes does not add one iota of traffic to the public or storage networks.

Yes it affects the memory interconnect used for cache fusion. But if that is your issue you have a very badly designed application.

> It's not just 5x cheap liliputians against the big expensive
> Gulliver.
>
> Then you've got the fun of your cluster fs and clusterware
> interacting over those 5x boxes.

And this is less than having two large boxes with DataGuard or Streams or Advanced Replication to attempt to achieve a high availability solution? Or do you just throw HA away?

> RAC requires more interesting and more expensive storage
> hardware then itself becomes an expensive single point of failure.

I'll gladly debate that with you any time you wish. The cost of RAW devices versus cooked file systems is? The cost of OCFS2 is? The cost of a NetApp or EMC differs how? The cost of ASM is?

>>But more importantly. You only have one box and zero failover. So double
>>the cost on your side, make that 2x10CPU boxes and be sure you have the
>>EE licenses for them. Then add DataGuard for failover.
>>
>>RAC is very reasonably priced when you consider everything required.

If you are paying 20K/cpu you are paying too much. I don't have a single customer that pays that much. And buy all the hardware you wish ... you still won't have FCF or FAN. You still won't have the ability to expand your systems incrementally. You still won't have all of the other valuable capabilities provided by RAC.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)