Re: Multiple DBs on One RAC - Adding New Nodes and Different Storage

From: D'Hooge Freek <>
Date: Thu, 26 Dec 2013 19:52:00 +0000
Message-ID: <1388087520.26883.199.camel_at_dhoogfr-lpt1>


You will at least need to make the ASM diskgroup holding the voting / ocr files visible on the new nodes as well. I have never tested what happens if not all ASM diskgroups are visible on all nodes, but I would expect to see some errors when creating / mounting new disk groups.

What would be the reason to not have all involved luns visible on all rac nodes? In my opinion, it would make it easier and flexible to have all asm luns visible on all nodes.

I don't understand what you mean with master node? If you want to dedicate one (or more nodes) for a application or database, you can use db services. In the service configuration you can mark some instances as preferred and other as available. There is also no requirement to create an instance on each of the nodes. You could for example have the following setup:

Database A, used by application X has instances on nodes 1,2 and 3. The db service used by application X has the instances on nodes 1 and 2 as preferred and on instance 3 as available (standby so to speak). Dabase B, used by application Y and Z has instances on nodes 3, 4 and 5. The db service used by application Y has the instances on nodes 3 and 4 as preferred and on instance 5 as available, while the db service used by application Z has nodes 4 and 5 as preferred an node 3 as available.

As you can see, you can play an puzzle with this as much as you want.

Kind regards,


Freek D'Hooge
Oracle Database Administrator
email:<> tel +32(03) 451 23 82

On do, 2013-12-26 at 13:22 -0600, David Barbour wrote: Merry Christmas (to those of you who celebrate), Happy Holidays (to those who may not but have something going on - including New Year's), and Good Afternoon:

We are currently running a 3-node RAC on RHEL 6.3(version 2.6.32-279.22.1.el6.x86_64), Oracle on ASM. Storage is fibre-connected EMC VMAX. Cluster cache communication is handled via Infiband. We are adding a new application and two nodes. The question arises with the storage. We're putting the new application on a Dell Compellent SAN. Also fibre connected. The plan is to make the 2 new nodes the primary nodes for this application, and make node 3 of the current cluster the fail-over.

Can anyone who has used multiple different SANs before provide any hints/tips/tricks/pitfalls?

Will we have to serve the current EMC Storage to the new nodes? I don't see why as we're not expanding the number of instances of the currently running application. But we will have to zone the new storage to connect to the third node of the current cluster. Any thoughts on how to install this new application? I don't really want instances of it on Nodes 1 & 2 at all. If I make Node 3 the master node and install from there, I should be able to pick Nodes 4 & 5 on which to create the other new instances.

Any thoughts?

-- Received on Thu Dec 26 2013 - 20:52:00 CET

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