Re: Oracle RAC on VM

From: Chip Briggs <chip.briggs_at_gmail.com>
Date: Thu, 21 Aug 2014 17:36:43 -0600
Message-ID: <CALrPUq-bQbjZ7C8cO-KG3zzYLHTz+X4JW8=Ma79ePHkG5+F_ew_at_mail.gmail.com>

Newer RAC hardware is Oracle's Exadata that can offload query filtering to storage subsystem. Oracle 12c Enterprise Edition has pluggable database option so Exadata hardware could be used to consolidate many Oracle databases.

Remember a lesson learned many years ago from Mogens Nørgaard <https://twitter.com/mnorgaard> that the Copenhagen Airport improved Oracle Database availability by switching from RAC to a single instance. Found a Sep 2012 blog =>
http://flashdba.com/2012/09/10/database-virtualisation-the-end-of-oracle-rac/ with links to “You Probably Don’t Need RAC” white paper plus VMWare vMotion that allows online migration of Oracle databases.

Crazy RAC bug is Oracle 10g clusterware not being able to handle Solaris HosT NaMes with MiXeD case. Workaround was changing a command to always return lower case host name.

Keep Smiling, Chip :)

On Thu, Aug 21, 2014 at 4:14 PM, Kevin Lidh <kevin.lidh_at_gmail.com> wrote:

> As a DBA, I never wanted to work on Oracle on VMware but it seems to be
> the trend. Now that I’m a manager, I’m looking to propose moving to RAC
> for HA and also back to physical machines. Since this goes against the
> strategic direction of our organization, I’m sure I’ll be asked why we
> can’t do RAC on VMs. I have my personal opinions about this but I was
> wondering what the broader audience of experts believe.
>
>
>
> Factors I’m considering are:
>
> 1) Servers closer to the storage for performance. In
> virtualization, you have an intermediary processing your requests and
> responses.
>
> 2) Access to all resources licensed. We keep a certain percentage
> of our hosts free to handle the load in case one in the cluster fails.
> With RAC, you have access to all the resources all the time. And since you
> have to pay for it all anyway, I see that as a good thing.
>
> 3) Performance in general. I don’t have any evidence but I can’t
> believe that another layer between my OS calls and the hardware could be as
> fast as not having that layer.
>
>
>
> Thanks in advance,
>
>
>
> Kevin
>

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Received on Fri Aug 22 2014 - 01:36:43 CEST