Question on RAC

Hi friends,
I have got this question from customer regarding Oracle 11G R2 RAC.
The customer have stated a preference for configuring the Oracle RAC nodes so that, in a two node system, the first node bears all the update load, whereas the second RAC node would have connections that are read-only. The two nodes would still operate as failovers for one another. The reason for this , they stated was to reduce network traffic between the nodes to coordinate transactions and locking. They have asked for this configuration as 'one update node and one read-only node' / a primary update node and a secondary read-only node .
We have thought about implementing this configuration for our two applications as follows
Application features
Application 1 - which performs regular updates,heavy transactions,long running reports et - schema 1
Application 2 - performs smalled updates and small reads. - schema 2
Application 1 can point to node 1 of this RAC and application 2 to node 2 ( using node affinity ).When any of the node fails , the client connections will fail over to surviving node.
I would like to get some recommendations on this approach from experts.
1) Do you think the above approach using node affinity is a good approach , ie pinning one schema in one node with one database for a two instance(node) RAC ?
2) Any documents / reference to configure this approach in RAC ?
3) Is there any other way to achieve the requirement put by the customer ?
4) If the above said nodes are in two data centres, Will it be a recommended approach ? I think these two nodes should be in same data centre.
5) If we configure Load balancing ( in normal RAC or in the setup mentioned above) then that would take considerable network b/w ?
OS is RHEL 5.4 on 64 bit.
Please share your view on this.
Thanks ,
SSN

1) Do you think the above approach using node affinity is a good approach , ie pinning one schema in one node with one database for a two instance(node) RAC ?In RAC , database remains same. So all schemas can be accessed from all nodes.
You can configure RAC services and then you can use one service for the updates and the other one can be used for read only application.
http://download.oracle.com/docs/cd/E11882_01/rac.112/e16795/hafeats.htm#BABJJJAG
4) If the above said nodes are in two data centres, Will it be a recommended approach ? I think these two nodes should be in same data centre.Why do you want to put RAC nodes in different data centers ?
You can use Oracle extended RAC in that case.
http://blogs.oracle.com/AlejandroVargas/2008/03/extended_rac_on_pure_oracle_st.html
http://www.databasejournal.com/features/oracle/article.php/3675096/Oracle-Extended-RAC-Stretching-your-RAC-to-the-limit.htm
Regards
Rajesh

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I was reading the article about installing the RAC.
My conclussion , I can have till 127 instaces of a Oracle 10G database, working simultane. That is good really good and powerfull.
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thanks for your help.

Is posting Question about RAC some kind of thought experiment on clustering? Like, if you post the same question several tyimes do you get faster answers?
Cheers, APC

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Hi,
We are thinking about build RAC using ASM for OEM database. It'll have two nodes, oracle 10g and Hitachi san with solaris ( or linux ). I've few questions about RAC and ASM.
1) Do I need to have ASM instance running on each node ? ( most likely yes... but want to make sure )
2) can I share oracle_home between ASM instance and database instance ? what is the best choice ?
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user4866039 wrote:
1) Do I need to have ASM instance running on each node ? ( most likely yes... but want to make sure )yes.
2) can I share oracle_home between ASM instance and database instance ? what is the best choice ?in 10g you can, in 11gr2 you cannot. and it might be better to seperate them because it will give you more flexibility with patching.
3) I'm planning to use shared disks for all files, all databases.... what are the pros/cons ?if you share your oracle_home you won't be able to do rolling updates. so i recommend to keep oracle_homes local.
4) what should be the installation procedure ? Meaning, first create ASM instance on each node, then install cluster software, build RAC databases...... can someone explain..follow the install guide for your respective version. for 10g you'd install clusterware first, then asm and database is last.
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Some Questions on RAC

Hi Experts,
What is GRD ? GRD Will reside on both instances..(Assuming two node Rac)?
Do we need to Install Oracle Binaries on Both nodes..!
Do we need to Install Cluster software on both nodes..!
Thanks
Manohar

Aman,
People (So Called DBAs) are simply opening the http://forums.oracle.com.... Comes directly in the forum and post the questions, without :
1.Providing OS and Oracle information
2.Do'nt bother to read the docs
3.Do'nt take pain for search in forum,google
4.Do'nt follow the forum etiquette (Even after saying.... :( )
Total Questions: 36 (33 unresolved)
I am surprised why this fellow is using the forum; which is only nearly 10% useful to him....!
I am sure, he will not respond any reply nor will close the thread.
Its really surprising how they are managing the world most advanced tech i.e. ORACLE.
Regards
Girish Sharma

Questions of RAC setup

Questions are:
1. How many voting disks do we need per cluster (considering we have a redundant Fibre-channel connections)?
2. How many OCR disks do we need and what is the recommended access (OCFS2 or RAW)?
3. How do we calculate the bandwidth needed for the cluster interconnect? We currently have configured 2 x 1Gbit Ethernet ports for this.
The installation is on "Oracle Enterprise Linux 5.2 x86_64" and Oracle RAC 10GR2 on IBM x3850 M2 Servers and IBM N-Series storage connected via redundant Fibre-channel switches. Using ASM for disk handling.

I believe there are two issues here.
The first is that raw devices will not be supported in future Linux kernels. Raw device is a logical (character device) layer for the actual physical (block) device. In Linux for example, this will be +/dev/raw/raw1+ and it will be the logical raw device for physical device +/dev/sdf+.
With 10.2 CRS, you no longer need to use a raw device - you can run CRS's OCR and voting disks directly on the physical device (as the kernel now support the O_DIRECT flag for I/O on physical devices too and a raw device interface is not needed). (see Metalink note 401132.1)
Thus raw devices (as in the logical device required to be created on a physical device) are already on the way out.
The second issue is that we need a means of allocating shared storage for the OCR and voting devices at CRS startup time. Which means we have two basic choices. We either allocate a device directly (via raw for example), or we install some 3rd party (non-CRS) software that creates a sharable device for us - such as gfs, ocfs, and so on.
The problem with additional software - it increases the number of moving parts for CRS and is another software layer that can fail. Which leaves something like using raw devices a better option (less complex).
But this choice is forced because there is no "+native method+" we can use. This has changed with 11.2 and later, as ASM now can provide that functionality for us.
However, if you are still on pre 11.2 CRS and RAC/ASM, what are your choices then? Using a cluster file system or raw is pretty much the only choices available. And in that respect, raw is the one that will cause less problems and issues and is the preferred option (from personal experience).

Question about RAC

I was reading the article about installing the RAC.
My conclussion , I can have till 127 instaces of a Oracle 10G database, working simultane. That is good really good and powerfull.
My questions
1º). ¿Can I have , by example, 3 , or any other number, of computer working with a HTMLDB instance or Oracle Aplication Server everyone serving pages to Internet and all then conect to one of those nodes? I think that yes, but prefer confirmation
2º) In case of failure of any of these nodes, broken computer ,by example, and I need to replace it, or I want add new nodes to a RAC system. ¿How I can do this? or ¿Where I can find documentation about this?
thanks for your help.

Have you checked the RAC installation guides? The biggest thing is to set up each set of interconnects on its own subnet to prevent routing issues.
Ssince I assume you are doing this for redundancy purposes, teamed NICs are another good idea that don't require a lot of re-configuration of Oracle.

General question about rac!!

hi all
I have a good experience in dba, and i prepare oca and ocp ,I want to learn important topics like (rac and tuning) .
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i have database 10g , vmware , windows 7 , windows server 2008 ..etc , what do I need exactly?
and I want good (tutorial , book video ..etc ) to learn Excellent .
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RAC Attack - Oracle Cluster Database at Home - Wikibooks, open books for an open world

Crs question for rac

on RH ES3 Update 5, Oracle 10.1.0.3....
Due to some network reconf. I reinstalled CRS.
I reconfigured VIPCA and NETCA.
My current status on this rac is:
VIP is running on node: hp1
GSD is running on node: hp1
Listener is running on node: hp1
ONS daemon is running on node: hp1
Problem: When I reboot, none of these resources come up automatically. How can i configure so that it can start during reboot.
Thanks in advance,
VT

The term rolling upgrade refers to upgrading different databases or different instances of the same database in a RAC environment, one at a time, without stopping the database. Oracle supports the rolling upgrade of Oracle RAC (not OS like I wrote previously) in a cluster when both versions of the operating system are certified with the version of the Oracle Database you are running. Rolling patch upgrades are not available if the Oracle Database software is shared across the different nodes. This is the case where the Oracle home is on Cluster File System (CFS) or on shared NFS volumes. The feature is only available where each node has its own copy of the Oracle Database software.
I doubt that Redhat or Oracle Linux will support in-place upgrades from version 4 to 5. Your only option really available might be to split the RAC cluster and completely setup each node from scratch, than rebuild the cluster. There could be of few changes between EL 4 and 5 that may affect your ability to run a mixed cluster, i.e. raw device support. Sorry, I'm afraid I cannot give you any other practical advise. Perhaps you might want to check the RAC forum at RAC, ASM & Clusterware Installation
To answer you question about the difference with Oracle Linux. The same versions of Oracle Linux and Red Hat Enterprise are binary compatible. For Oracle Linux 5.5, x86_64, you have an option to install the Unbreakable Enterprise Kernel (UEK), which contains a newer and Oracle optimized version of the kernel, currently 2.6.32. Oracle Linux provides a free public yum repository for software management and other Oracle specific packages. For access to patches you need a subscription to the Unbreakable Linux Network (ULN).
http://www.oracle.com/us/technologies/linux/index.html
http://www.oracle.com/us/corporate/pricing/els-pricelist-070592.pdf
https://www.redhat.com/apps/store/server/
Edited by: MaC on Dec 20, 2010 7:20 PM

Storage related question for RAC

Hi Gurus,
I have a question here about the storage design. My company has 2 node Oracle RAC already setup on Linux with 11g for clusterware, ASM and 10g for database(for application support we are using still 10g for database). This RAC is dedicated for one database and shared by several applications.
Now, we decided to add two more nodes and additional storage to it.
The existing storage uses EMC SAN DMX 4574 (raw partitions) disks. And the additional storage disks provided by our storage team are EMC SAN DMX 3752.
Is it possible to combine these two different DISK (different series from same vendor) into one single storage sub system visible to entire RAC Database? All the 4 nodes will be used for the same database and application. Its a production system so we wanted to confirm and proceed further as we dont have a test scenario.
Shall we connect these different disks to the switches so that ASM can see all the disks at once and can be used for database?
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Regards,
vasu
Edited by: vasu77 on Feb 23, 2010 10:12 AM

Hi Vasu,
The existing storage uses EMC SAN DMX 4574 (raw partitions) disks. And the additional storage disks provided by our storage team are EMC SAN DMX 3752.
Is it possible to combine these two different DISK (different series from same vendor) into one single storage sub >system visible to entire RAC Database? All the 4 nodes will be used for the same database and application. Its a >production system so we wanted to confirm and proceed further as we dont have a test scenario.First of all, You have to ask the OS support team in order to see if there is any kind of problem mixing it. I don't think it would be a problem, but as you don't have any test environemnt, You'd better ask them.
For the ASM side, it's not a problem, You can work with this kind of configuration. In fact I have a couple of environemnt using this configuration. I'm using a expensive storage with a better performance to critical tablespaces, and a lower cost storage to put historical data and other kind of data that are not accessed every time.
Shall we connect these different disks to the switches so that ASM can see all the disks at once and can be used for database? Well,
As I told before, I don't think it would be a problem, but again... You should ask the OS support team. For the ASM side, You shouldn't mix disks with diferent behaviour in the same diskgroup, You should use disks with the same size and similar/equal performance characteristics. As ASM balances the I/O over the disks in a ASM diskgroup, it's important to configure in this way in order to avoid performance problems.
Hope it helps,
Cerreia

Question about RAC 10g on server running AIX and domain name changes

We have several 10g clusters running on IBM p-Series AIX servers, and our company is changing the domain name for our network. I am concerned that if we do not change the domain names in the TNSNAMES.ora file and also the /etc/hosts file on each server, the cluster will no longer function. We are using CRS (version 10.2.0.3) and ASM within each cluster.
Does anyone know where I can find information about changing the domain name that was set up as part of the CRS and database installs for RAC? Does anyone have experience doing this, and would be willing to share a few insights? Thanks in advance for any advice you can give!

You may be able to use the VIPCA utility for RAC to change or modify the public and private settings for your domain names on AIX. Also, the Oracle 10g DBCA "Database Configuration Assistant" should be of use to change your settings for your RAC environment.
Also, see here for a good IBM Redbook that covers Oracle 10g RAC on AIX platforms:
http://www.redbooks.ibm.com/redbooks/pdfs/sg247541.pdf
Regards,
Ben Prusinski
http://oracle-magician.blogspot.com/
Regards,
Ben Prusinski
http://oracle-magician.blogspot.com/

Few Question on Rac

Hi Experts ,
I am new to the RAC , wanted to clear some doubt : Version 10.2.0.4 , dedicated process
Their is concept of local listener and Remote Listener in Rac. I understand these are used internally for load balancing. Please correct me If I am wrong.If I provide the user tns details and having the enteries of one node (node 1) only and that node ( node 1) is heavily loaded. In that case load balancing takes place at listener level ? If yes How. Since Generally their is shadow process (server process) is created on server after the listener hand shake is done. And that process directly communicated with client process. So In rac if load balancing takes place then how the client will connect to node 2.
Their is concept of VIP. Generally it is used to provide the High Availability. If the user query is runnning on node 1 and node 1 crashes, without knowing the user it will proccess the query from node 2.What kind of query can be executed ? Select , Insert , delete update . I heard that select will be executed but insert delete and update will be failed . Is that correct.
REgards
Sourabh Gupta

Their is concept of local listener and Remote Listener in Rac. I understand these are used internally for load balancing. Please correct me If I am wrong.If I provide the user tns details and having the enteries of one node (node 1) only and that node ( node 1) is heavily loaded. In that case load balancing takes place at listener level ? If yes How. You connect to service, not to sid. The service can run on multiple instances. Each instance every minute connects to local and remote listeners (if defined) and updates its services and load. So listener can balance connections among instances.
>
Their is concept of VIP. Generally it is used to provide the High Availability. If the user query is runnning on node 1 and node 1 crashes, without knowing the user it will proccess the query from node 2.What kind of query can be executed ? Select , Insert , delete update . I heard that select will be executed but insert delete and update will be failed . Is that correct.In 10g clients connect to VIP. If node fails, its VIP moves to another node. TAF does not require VIP, it was availiable before 10g.

Question on RAC on SAN

Hi all,
can sombody tell me if we are using SAN as a shared storage do we get raw devices as mpunt points or do we get iscsi deices? what we will the partition types we get when we use SAN as our storage?
Thanks
Maverick

What is the application release? DB version? Do you have RAC implemented?
You can use any filesystem as long as it is supported with your application/database -- See the links below for some details.
Is It Safe to Use SANs for EBS R12 Instance Tops?
http://blogs.oracle.com/stevenChan/2009/08/local_disk_vs_san_for_inst_tops.html
OCFS2 for Linux Certified for E-Business Suite Release 12 Application Tiers
http://blogs.oracle.com/stevenChan/2010/03/ocfs2_linux_certified_ebs12.html
Choosing a Shared File System for Oracle E-Business Suite
http://blogs.oracle.com/stevenChan/2009/07/choosing_an_ebs_shared_file_system.html
Thanks,
Hussein

Question on RAC Failover testing

Can someone point me to RAC Fail-over testing strategies?
Thanks,
Subroto

It totally depends on your application and your setup. Using TAF ? Using Load Balancing ? Using OCFS ? Using ASM ?
Kill the sqlnet listener and see what happens.
Kill the database pmon and see what happens.
Kill the ASM dbwr and see what happens.
Kill crsd and see what happens.
Shutdown the VIP interface and see what happens.
Shutdown the interconnect interface and see what happens.
Pull the power plug out and see what happens.

Basic question on RAC in Dataguard

RDBMS version : 10GR2
If my Primary DB is in RAC , should my Standby DB (Physical or Logical) be in RAC as well ?

Although all combinations are technically possible:
1) RAC Primary & Single Instance Standby
2) Single Instance Primary & RAC Standby
3) RAC Primary & RAC Standby,
the most common case is indeed 3)
1) will be probably not used for DR but for Reporting only
2) will be used during Migration to RAC
typically.
Kind regards
Uwe Hesse
http://uhesse.wordpress.com

Question about RAC DB.

Hi all,
I have problem with RAC 11gR2 database.
I have 2 node configured in RAC environment, RAC1 in Linux_1 and RAC2 on Linux_2.
After RAC environment reboot I discovered that my databases started up in different nodes. RAC1 DB stared on Linux_2 and RAC2 on Linux_1. I tried to restart database with srvctl command but unfortunately I got same results.
Please help me to understand how to start each DB exactly on node which I want and how avoid from this situation.
My environment Grid Infrastructure /RAC/ASM/SCAN/GNS11gR2 on OEL 5.7.
./thanks

909592 wrote:
Hi above example which i gave will do something like this in background.
1) It will update the OCR and modify configuration of Instance, it will tell cluster that on which node instance has to start
2) It will update the instance dependency on ASM running under this node.
So first we modify the OCR to tell cluster that instance1 has to run on node1 and secondly cluster will see it is depended upon ASM1.
thanks everything is clear now !
To see configuration you can run
srvctl config database -d databasenameHere my output
*[grid@rac1 ~]$ srvctl config database -d rock*
Database unique name: ROCK
Database name: ROCK
Oracle home: /u01/app/oracle/product/11.2.0/db_1
Oracle user: oracle
Spfile: +CLOUD/ROCK/spfileROCK.ora
Domain:
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: DBSP
Database instances: rock_1,rock_2
Disk Groups: CLOUD,FRA
Services:
Database is enabled
Database is policy managed
So how can I find out that RAC1 instance will start only on RAC1 node ?

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