RE: Multiple DBs on One RAC - Adding New Nodes and Different Storage
- From: "Mark W. Farnham" <mwf@xxxxxxxx>
- To: <david.barbour1@xxxxxxxxx>, "'oracle-l mailing list'" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 26 Dec 2013 15:46:49 -0500
My first question is "what do you mean by fail-over?"
IF someone asked me about adding nodes to host a new application to a shop
with a new disk farm from a different vendor than the existing one, I'd be
inclined to keep them separate and make this a standby recovery (home rolled
or possibly passive or active dataguard, depending on your licenses and
requirements for time until application use resumes) rather than increasing
the complexity of the existing ASM complex.
You would need to be able to write from lgwr or arch to some location that
the nodes on the existing cluster can see, but that seems a lot less
demanding a storage task to me than fully integrating new storage and nodes
into ASM. And since they would fail separately, I think your overall
availability would increase. Quite possibly the two new nodes might serve as
standby recovery targets for the existing cluster in case that ASM complex
fails.
On the other hand if the peaks and valleys of your applications across time
are such that some might benefit from 5 nodes enough of the time to make it
worth the trouble, then I think the best way to go is to fully integrate the
ASM requiring, as Tim wrote, at least visibility to the configuration and
coherency bits of ASM. You might make disk groups exclusively on the new
storage, but at least one node of the first three will need to be able to
see that disk to facilitate rac instance type fail over (as opposed to
standby failover).
To make a real recommendation we'd need to know a lot about your mission,
goal, and resources.
mwf
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of David Barbour
Sent: Thursday, December 26, 2013 2:23 PM
To: oracle-l mailing list
Subject: Multiple DBs on One RAC - Adding New Nodes and Different Storage
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 11.2.0.3.0 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?
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