RE: Extended RAC and multicast
From: Iggy Fernandez <iggy_fernandez_at_hotmail.com>
Date: Wed, 16 Apr 2014 10:30:13 -0700
Message-ID: <BLU179-W429CF85DCF602B2EB9F39EB530_at_phx.gbl>
Hi, Tim,
The customer bought the story (in the Extended RAC white paper) that Extended RAC provides some measure of Disaster Recovery (with the emphasis on some). The white paper is at http://www.oracle.com/technetwork/products/clustering/overview/extendedracversion11-435972.pdf.
"Unlike classic Oracle RAC implementations, which are primarily designed as scalability and high availability solution that resides in a single data center, it is possible – under certain circumstances – to build and deploy an Oracle RAC system in which the nodes are separated by greater distances. For example, if a customer has a corporate campus, they might want to place the individual Oracle RAC nodes in separate buildings. This configuration provides a higher degree of disaster tolerance, in addition to the normal Oracle RAC high availability, since a fire in one building would not, if properly set up, stop the database from processing. Similar, many customers have two data centers in reasonable proximity (<100km) which are already connected by a direct, ideally non-routed, high speed link(s) and are often on different power grids, flood plains, and the like."
"Oracle RAC on Extended Distance Clusters does not constitute a different type of cluster, neither is there a special installation option that one can choose from. This means that as far as the configuration of the system is concerned, the main goal is to hide the fact that Oracle RAC is now operating over distance. On the other hand, this means that the basic configuration remains the same, including its requirements. Attention must be paid when configuring the network and storage connectivity for Extended Distance Oracle RAC environments."
Iggy
Date: Wed, 16 Apr 2014 10:30:13 -0700
Message-ID: <BLU179-W429CF85DCF602B2EB9F39EB530_at_phx.gbl>
Hi, Tim,
The customer bought the story (in the Extended RAC white paper) that Extended RAC provides some measure of Disaster Recovery (with the emphasis on some). The white paper is at http://www.oracle.com/technetwork/products/clustering/overview/extendedracversion11-435972.pdf.
"Unlike classic Oracle RAC implementations, which are primarily designed as scalability and high availability solution that resides in a single data center, it is possible – under certain circumstances – to build and deploy an Oracle RAC system in which the nodes are separated by greater distances. For example, if a customer has a corporate campus, they might want to place the individual Oracle RAC nodes in separate buildings. This configuration provides a higher degree of disaster tolerance, in addition to the normal Oracle RAC high availability, since a fire in one building would not, if properly set up, stop the database from processing. Similar, many customers have two data centers in reasonable proximity (<100km) which are already connected by a direct, ideally non-routed, high speed link(s) and are often on different power grids, flood plains, and the like."
"Oracle RAC on Extended Distance Clusters does not constitute a different type of cluster, neither is there a special installation option that one can choose from. This means that as far as the configuration of the system is concerned, the main goal is to hide the fact that Oracle RAC is now operating over distance. On the other hand, this means that the basic configuration remains the same, including its requirements. Attention must be paid when configuring the network and storage connectivity for Extended Distance Oracle RAC environments."
Iggy
- Iggy FernandezEmail: iggy_fernandez_at_hotmail.comCellphone: (925) 478 3161Blog: So Many Manuals So Little Time Author of Beginning Oracle Database 11g AdministrationEditor of the NoCOUG JournalLecturer at University of Washington Professional and Continuing Education
Date: Wed, 16 Apr 2014 09:36:25 -0600
From: tim_at_evdbt.com
To: oracle-l_at_freelists.org
Subject: Re: Extended RAC and multicast
Iggy,
Not to open any cans of worms (and please feel free to not answer
this question for any reason), but why did they choose an
"extended RAC" deployment in the first place, as opposed to any of
the Data Guard options? Do they already use Data Guard? Was
there something that "extended RAC" (or "geographically-dispersed
cluster" technology) does better than Data Guard (or database
replication technology) in general?
Just curious...
Thanks!
-Tim
On 4/16/2014 9:21 AM, Iggy Fernandez wrote:
Thank you
very much Martin.
We found additional
information on the multicast requirement at the following
link:
http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/UCS_CVDs/cisco_ucs_oracle_rac.html#wp439295
Kindest regards,
Iggy
--
Iggy Fernandez
Email: iggy_fernandez_at_hotmail.com
Cellphone: (925) 478 3161
Blog: So Many Manuals So Little Time
Author of Beginning Oracle Database 11g
Administration
Editor of the NoCOUG Journal
Lecturer at University of Washington Professional
and Continuing Education
From: martin.a.berger_at_gmail.com
Date: Mon, 14 Apr 2014 20:46:39 +0200
Subject: Re: FW: Extended RAC and multicast
To: iggy_fernandez_at_hotmail.com
CC: oracle-l_at_freelists.org; kulkarniravi_at_yahoo.com
Iggy, Ravi,
from all my test I call multicast a requirement
from 11.2.0.2 onwards.
Take care about the different Multicast networks
possible in different Patch-Sets!
As you are talking about VLAN_S_ - I'd not do
anything than pure switched private network.
Everything else will lead to troubles sooner or
later.
My .02€
Martin
On Mon, Apr 14, 2014 at
8:29 PM, Iggy Fernandez <iggy_fernandez_at_hotmail.com>
wrote:
A friend
asked me a question that I could not
answer. He is in the planning stages of an
"extended RAC deployment" and is looking
for confirmation that multicasting is
optional.
Help would
be appreciated.
Kindest
regards,
Iggy
--
Iggy Fernandez
Email: iggy_fernandez_at_hotmail.com
Cellphone: (925) 478 3161
Blog: So Many Manuals So
Little Time
Author of Beginning Oracle
Database 11g Administration
Editor of the NoCOUG Journal
Lecturer at University of Washington
Professional and Continuing Education
Date: Mon, 14 Apr 2014 11:13:03 -0700
From: kulkarniravi_at_yahoo.com
Subject: Extended RAC and multicast
To: iggy_fernandez_at_hotmail.com
I am looking to setup
extended RAC for my client. The details
are as following:
The two data centers are separated by a
distance of less than 20 miles.
They are connected by a high speed
dedicated connection.
Operating System: RHEL 6 64 bit
Database version: 11gR2 (11.2.0.3)
Hardware: Four servers with 4x16
configuration
All the documentation I have reviewed so
far says multicast should be enabled on
the private interconnect between all the
nodes
of a RAC database. However, my network
resources tell me that multicasting is not
enabled across the data centers and VLANs
do not span across the data centers. The
only reference I have seen to multicasting
requirement is in this Oracle document:
http://docs.oracle.com/cd/E16655_01/install.121/e17888/networks.htm#CWLIN476
Specifically it makes the following
assertion:
"You do not need to enable multicast
communications across routers"
Does this mean, multicast is optional?
Regards,
Ravi Kulkarni
-- http://www.freelists.org/webpage/oracle-lReceived on Wed Apr 16 2014 - 19:30:13 CEST