Does Oracle RAC improve performance over single-instance db

Hallo!i am running a single instance db that seems to be overwhelmed by workload as CPU is constantly 100% utilized despite code and instance tuning and users persistently complain of system slowness.
It is our plan to uprgade to more powerful servers but would also like to implement load balancing to have 2 instances and 2 servers share workload via RAC solution.
Some of peers state that RAC mostly a High Availability solution to enable continuity should one instance fail.I would like to know if db performance would improve on RAC as load balancing between 2 or more instances occurs in a RAC setup.
Thanks.

4joey1 wrote:
Some of peers state that RAC mostly a High Availability solution to enable continuity should one instance fail.I would like to know if db performance would improve on RAC as load balancing between 2 or more instances occurs in a RAC setup.RAC also provides scalability - as you have additional servers and database instances to deal with the workload. It is not a mere high availability and redundancy architecture.
BTW, a 2 node RAC is IMO not a "real" RAC... We also have one of those and I regret not insisting that it be, at minimum, a 4 node RAC - from both a redundancy/availability and performance/scalability viewpoints.
Simple example - on our bigger RAC we are dealing with about 37000+ row inserts every second (3+ billion rows per day). This workload is only handled (on smallish dual 2-core CPU servers) due to RAC. No way that a single one of these servers would alone (as a single non-RAC instance) be capable to deal with that workload.
So yeah - RAC is most definitely also about performance and scalability too. (but that does not mean it's a magic wand for solving your performance problems either).

Similar Messages

How does a RAC DB 'spread' from single instance to multiple instances ?

GI/RDBMS Version: 11.2.0.3
OS: Oracle Linux 6.3
Filesystem : ASM
When a RAC database is created using dbca , Manually , or RMAN restore, the DB is created in the Node1 first with cluster_Database=FALSE .
Then you run the following commands (for 3-node RAC) from Node1
srvctl add database -d lmnprod -o $ORACLE_HOME -p +LMNPROD_DATA01/lmnprod/spfilelmnprod.ora
srvctl add instance -d lmnprod -i lmnprod1 -n hwcarser290
srvctl add instance -d lmnprod -i lmnprod2 -n hwcarser291
srvctl add instance -d lmnprod -i lmnprod3 -n hwcarser292
Once the DB is created,mounted and opened in Node1 and the above commands are executed , you set cluster_Database=TRUE and startup the Instance2 and Instance 3 in Node2 and Node3.
I just want to know how does Node2 and Node3 becomes aware of the DB and joins the DB cluster ? What happens internally ?

Generally speaking, registering in OCR is not required for database to be a cluster database.
Migration from single-instance database to cluster consists of creating redo logs and undo tablespace for new instance and enabling this instance (thread). If database is policy-managed, this is done automatically for new node.

Benefit of RAC over single instance

Dear,
There would be up-gradation of our main system from oracle 10.2.0.4 to 11.2.0.4. The management wants to stay on single instance as it is now. But Oracle RAC is something that is must for all the critical system I need to present the benefit of RAC over single instance considering the high cost. Can you show me the benefits of RAC that ppl would go for it instead of single instance????

Hi,
The Benefits of Oracle Real Application Clusters.
High Availability-Oracle Real Application Clusters 11g provides the foundation for data centre-high availability. It is also
an integral component of Oracle’s Maximum Availability Architecture, which provides best practices to
provide the highest availability for your data center. Oracle Real Application provides the following ke
characteristics essential for a high available data management
Reliability – The Oracle Database is known for its reliability. Oracle Real Application Clusters takes this
a step further by removing the database server as a single point of failure. If an instance fails, the
remaining instances in the server pool remain open and active. Oracle Clusterware monitors all Oracle
processes and immediately restarts any failed component.
Recoverability – The Oracle Database includes many features that make it easy to recover from all
types of failures. If an instance fails in an Oracle RAC database, it is recognized by another instance in
the server pool and recovery will start automatically. Fast Application Notification (FAN) and Fast
Connection Failover (FCF) or Transparent Application Failover (TAF) make it easy for applications to
mask component failures from the user.
Error Detection – Oracle Clusterware automatically monitors Oracle RAC databases as well as other
Oracle processes (ASM, listener, etc) and provides fast detection of problems in the environment. It also
automatically recovers from failures often before users noticed that a failure has occurred. Fast
Application Notification (FAN) provides the ability for applications to receive immediate notification of
cluster component failures in order to re-issue the transaction before the failure surfaces.
Continuous Operations – Oracle Real Application Clusters provides continuous service for both
planned and unplanned outages. If a server (or an instance) fails, the database remains open and the
application is able to access data. Most database maintenance operations can be completed without
downtime and are transparent to the user. Many other maintenance tasks can be done in a rolling
fashion so application downtime is minimized or removed. Fast Application Notification and Fast
Connection Failover assist applications in meeting service levels.
Scalability-Oracle Real Application Clusters provides a unique technology for scaling applications. Traditionally,
when database servers ran out of capacity, they were replaced with new and larger servers. As servers
grow in capacity, they are more expensive. For databases using Oracle RAC, there are alternatives for
increasing the capacity. Applications that have traditionally run on large SMP servers can be migrated to
run on pools of small servers. Alternatively, you can maintain the investment in the current hardware and
add a new servers to the pool (or to create a server pool) to increase the capacity. Adding servers to a
server pool with Oracle Clusterware and Oracle RAC does not require an outage and as soon as the new
instances are started, the application can take advantage of the extra capacity. All servers in the server pool
must run the same operating system and the same version of Oracle, but they do not have to be of exactly
the same capacity. Customers today run server pools that fit their needs often using servers of (slightly)
different characteristics.
http://www.oracle.com/technetwork/database/clustering/overview/twp-rac11gr2-134105.pdf

Converting to Oracle Real Application Clusters from Single-Instance Oracle

Is there any notes at metalink for
Converting to Oracle Real Application Clusters from Single-Instance Oracle Databases
We should have 10g DB on ASM to make it RAC?

With Oracle Database 10g Release 2, $ORACLE_HOME/bin/rconfig tool can be used to convert Single instance database to RAC. This tool takes in a xml input file and convert the Single Instance database whose information is provided in the xml. You can run this tool in "verify only" mode prior to performing actual conversion. This is documented in the RAC admin book and a sample xml can be found $ORACLE_HOME/assistants/rconfig/sampleXMLs/ConvertToRAC.xml. Grid Control 10g Release 2 provides a easy to use wizard to perform this function.

CONVERTING TWO NODE RAC ON WINDOWS TO SINGLE INSTANCE

I got question about a two node RAC on Windows.
One of our vendors is hosting our oracle enviroment and we are planning to bring in the datacenter in house and manage it ourselves.
Current they have a two node RACon windows
The new enviroment we are building here , we want to get rid of RAC and bring it back to a single instance environment.
How do i approach this?
1. My first option was to create a new database server and do the export dp from one of the node and import to the new single instance enviroment.
My conncern is can you do export from RAC database and import it to a non RAC enviroment?
2. My second option is to delete one node on the two node RAC and then do export dump or cold backup and copy the database files and necessary config files.
let me know how i can approach this.....

Okay guys after digging aroung i found the following approach.....
Cloning Oracle 10gR2 from RAC Environment to Single Instance Environment will raise the following error
ORA-29702: Error occurred in Cluster Group Service Operation.
The new instance is looking for CRS on new single instance non RAC environment.
For UNIX platform follow the following steps:
- Shutdown the instance which is cloned to non RAC.
- Shutdown all the listeners.
- Relink Oracle executable with rac_off option.
$ make -f ins_rdbms.mk rac_off
$ make -f ins_rdbms.mk ioracle
- Remove all the parameters from init.ora which points to second instance
and it is on other node.
- Remove cluster_database parameter
- Remove undo_tablespace parameter which points to second instance
For Windows Platform follow the following steps:
- Shutdown the instance which is cloned to non RAC.
- Shutdown all the listeners.
- Rename following file in %ORACLE_HOME%/bin directory: orarac10.dll to orarac10.dll.bak
Give me your thoughts, there is nothing on Metalink....

Any solutions from oracle to improve Performance in Oracle Jdeveloper 10g

Hi ,
We are developing ADF Applications in Oracle Jdeveloper 10g , 4 developers are working . now every one M/c Ram upgraded to 4 GB
Still my developers are getting Performance issue , Like Java Heap memory Reached . when we saw in Task Manager Memeusage reached 450,000K
then Jdeveloper dies and hang there . we have to do this at least 4 to 5 times everyday . thats where it taking a lots of time to
modify a single small changes .
What our deveoper are doing they trying to commit frequently after making a important changes in application . but sometimes developer are also
forget in between . So wee need a solution for this if Oracle fixes this issue .
Thanks
KP

Hi,
We never had that issue with 10g (but happens in 11g), what is the project's size? I assume very big, else your environment must have something fishy, 10g is really fast and lightweight.
Regards,
~ Simon

Oracle RAC interconnect performance by GRIDControl

Hi All,
We have Oracle 10g Rac and we manage database through Grid control.
We are not able to see <Performance> and <Interconnects> tabs in rac cluster page , do you guys know why?
logged into sysman--> at right corner <targets> at left side I could see database list , I selected Rac database name and clicked --> at the top left most corner I see a link like below, so if I click on this hyper link (DBname) it is taking me to cluster page, here it is not able to enable two tabed pans <Performance> and <Interconnects> can anyone please help me how to check this information in Grid Control
Cluster: DBNAME >
Thanks in advance

First click on the target type Cluster Database, that will take you to overall Cluster Database : <your cluster database name> page. There on the top of the page, left side you will see a hyperlink with name Cluster: <cluster name>, click on this cluster name hyperlink that will take you to the Cluster page where interconnect tabs are enabled.
-Harish Kumar Kalra

How can I improve performance over a Branch Office IPsec vpn tunnel between and SA540 and an SA520

Hello,
I just deployed one Cisco SA540 and three SA520s.
The SA540 is at the Main Site.
The three SA520s are the the spoke sites.
Main Site:
Downstream Speed: 32 Mbps
Upstream Speed: 9.4 Mbps
Spoke Site#1:
Downstream Speed: 3.6 Mbps
Upstream Speed: 7.2 Mbps (yes, the US is faster than the DS at the time the speed test was taken).
The SA tunnels are "Established"
I see packets being tranmsitted and received.
Pinging across the tunnel has an average speed of 32 ms (which is good).
DNS resolves names to ip addresses flawlessly and quickly across the Inter-network.
But it takes from 10 to 15 minutes to log on to the domain from the Spoke Site#1 to the Main Site across the vpn tunnel.
It takes about 15 minutes to print across the vpn tunnel.
The remedy this, we have implemented Terminal Services across the Internet.
Printing takes about 1 minute over the Terminal Service Connection, while it takes about 15 minutes over the VPN.
Logging on to the network takes about 10 minutes over the vpn tunnel.
Using an LOB application takes about 2 minutes per transaction across the vpn tunnel; it takes seconds using Terminal Services.
I have used ASAs before in other implementation without any issues at all.
I am wondering if I replaced the SAs with ASAs, that they may fix my problem.
I wanted to go Small Business Pro, to take advantage of the promotions and because I am a Select Certified Partner, but from my experience, these SA vpn tunnels are unuseable.
I opened a case with Small Business Support on Friday evening, but they couldnt even figure out how to rename an IKE Policy Name (I figured out that you had to delete the IKE Policy; you cannot rename them once they are created).
Maybe the night weekend shift has a skeleton crew, and the best engineers are available at that time or something....i dont know.
I just know that my experience with the Cisco TAC has been great for the last 10 years.
My short experience with the Cisco Small Business Support Center has not been as great at all.
Bottom Line:
I am going to open another case with the Day Shift tomorrow and see if they can find a way to speed things up.
Now this is not just happening between the Main Site and Spoke Site #1 above. It is also happeninng between the Main Site and Spoke #2 (I think Spoke#2 has a Download Speed of about 3Mbps and and Upload Speed of about 0.5 Mbps.
Please help.
I would hate to dismiss SA5xx series without making sure it is not just a simple configuration setting.

Hi Anthony,
I agree!. My partner wants to just replace the SA5xxs with ASAs, as we have never had problems with ASA vpn performance.
But I want to know WHY this is happening too.
I will definitely run a sniffer trace to see what is happening.
Here are some other things I have learned from the Cisco Small Business Support Center (except for Item 1 which I learned from you!)
1. Upgrade the SA540 at the Main Site to 2.1.45.
2a. For cable connections, use the standard MTU of 1500 bytes.
2.b For DSL, use the following command to determine the largets MTU that will be sent without packet fragmentation:
ping -f -l packetsize
Perform the items below to see if this increases performance:
I was told by the Cisco Small Business Support Center that setting up a Manual Policy is not recommended; I am not sure why they stated this.
3a. Lower the IKE encryption algorithm from "AES-128" to DES.
3b. Lower the IKE authentication algorithm to MD5
3c. Also do the above for the VPN Policy
Any input is welcome!

Protect single instance linux Oracle 11Gr2 with Clusterware 11Gr2 non-RAC

Hi All,
I saw this link, but it mentions RAC as a solution:
Using Oracle Clusterware to Protect A Single Instance Oracle Database 11g
I have seen various articles about protecting single instance with cold failover using clusterware, but they mention scripts and older versions of Clusterware. I am trying to figure out if possible to incorporate virtual ip's / scan listeners or if this is even a supported configuration...
I have set up clusterware 11gr2 using OCFS2. I basically just want to do a cold failover from one node to the other, and I do not wish to purchase a RAC license...
thanks much
Edited by: vcovco on Sep 30, 2010 1:52 PM

Below are the steps which i followd. Can you pls take a look & reply if the below are correct.
Step1 rg1
crsctl add resource rg1 -type cluster_resource \
-attr "ACTION_SCRIPT=$CRS_HOME/crs/public/act_resgroup.pl, \
CHECK_INTERVAL=600"
./crsctl start resource rg1
Step2 rg1.vip
As root
$CRS_HOME/bin/appvipcfg create -network=1 -ip=xx.xx.xx.xx -vipname=rg1.vip -user=root -group=root
./crsctl setperm resource rg1.vip -u user:oracle:r-x
./crsctl start resource rg1.vip
Step3 rg1.listener
export CRS_HOME=/optware/grid/11.2.0.2
export ORACLE_HOME=/optware/oracle/11.2.0.2/db
export USRORA_LANG=$ORACLE_HOME
export USRORA_SRV=LISTENER_rg1
export ORACLE_SID=rg1
$CRS_HOME/crs/public/act_listener.pl start
Listener.ora
=========
LISTENER_rg1=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=lxwkbc-app)(PORT=1320))))
Tnsnames.ora
=========
LISTENERS_rg1 =(ADDRESS_LIST =(ADDRESS = (PROTOCOL = TCP)(HOST = lxwkbc-app)(PORT = 1320)))
./crsctl add resource rg1.listener -type cluster_resource \
-attr "ACTION_SCRIPT=$CRS_HOME/crs/public/act_listener.pl, \
CHECK_INTERVAL=20,RESTART_ATTEMPTS=5, \
START_DEPENDENCIES=hard(rg1.vip) pullup(rg1.vip),STOP_DEPENDENCIES=hard(rg1.vip)"
./crsctl start resource rg1.listener
Step4 rg1.db_rg1
export CRS_HOME=/optware/grid/11.2.0.2
export ORACLE_HOME=/optware/oracle/11.2.0.2/db
export USRORA_LANG=$ORACLE_HOME
export USRORA_SRV=rg1
export ORACLE_SID=rg1
export USRORA_FLAGS=1
$CRS_HOME/crs/public/act_db.pl stop
./crsctl add resource rg1.db_rg1 -type cluster_resource \
-attr "ACTION_SCRIPT=$CRS_HOME/crs/public/act_db.pl, CHECK_INTERVAL=20,RESTART_ATTEMPTS=5, \
START_DEPENDENCIES=hard(rg1.listener) pullup(rg1),STOP_DEPENDENCIES=hard(rg1.listener)"
./crsctl start resource rg1.db_rg1
Step5 rg1.head
./crsctl add resource rg1.head -type cluster_resource \
-attr "ACTION_SCRIPT=$CRS_HOME/crs/public/act_resgroup.pl, CHECK_INTERVAL=600,RESTART_ATTEMPTS=2, \
START_DEPENDENCIES=hard(rg1.listener,rg1.db_rg1,rg1)"
./crsctl start resource rg1.head

Oracle RAC scalability(does it linearly scalable upto 20-30 nodes)

We are looking datastorage solution as Oracle -RAC for following performance requirement
Application is generating Resources which we want to store in database and provide searching on this resources.
Resource have 2 part one is data and another one is meta
Data contains textual/binray data like txt/html/doc/excel/pdf/image file etc
meta contains 30-40 different property telling something about data.
Average resource size is 10K
Insertion speed required for such resource (Data + Meta ) 2Gbps(30K Resource/Second )
We want indexing also on data and meta.
We used single oracle database and created resource table which has 40 column for meta property and one column of blob type for data.
Performance achieved is 100Mbps insertion speed (on normal machine)
Now to go to 2Gbps we are thinking to use Oracle RAC to scale it up to 2Gbps Insertion speed.May be 20 Node is required to scale it upto 2Gbps.
Now my question is does Oracle RAC provide close to liener scalability upto 20-30 nodes or not.
Key requirement is to achieve insertion speed upto 2Gbps
High availability of oracle rac can be added advantage for us but key concern here is scalability not fault tolerance.

> Now we are not using oracle partitioning because it
is slow when we define domain index (even index is
local and it is not sync real time ,index maintaines
is off) but it maintains pending queue and which
slows down insertion process.
Hmm.. I'm using partitioning extensively for mass parallel inserts and it is a lot cleaner than individual tables (requiring dynamic SQL), and I have not seen any performance issues.
Can you elaborate on what issues you have seen?
> Our main and key concern is to achieve insertion
speed of 2Gbps initialy and should be scalable upto
10Gbbps.
May I ask what data you are collecting? This volume sounds a bit extreme - is something like collecting/sniffing UDP/TCP packets?
> 1.If we have say I/O and network bandwidth available
then does oracle RAC will be capable to consume this
available I/O and network bandwidth by adding more
nodes.
Yes. Remember that each cluster node has its own set of local platform resources - including a pipe to the shared storage (such as a I/O fibre channel).
What will cause an impact? Anything that will impact a single insert process will also impact that process across a cluster. E.g. two processes attempting to insert a row with the same PK - only one can succeed and thus one will be blocked by another. Bitmap indexing as a lock on a bitmap "slot" locks the index data for a number of rows - any of which can currently be updated by other processes. Etc.
How is this resolved in a cluster? As the processes are not local to the same platform, IPC cannot be used. Thus it means the Interconnect has to be used. This will be slower than IPC.
> 2.We also heard from HP that Interconnect of node
will be botteleneck for us but my question is if we
look at above scenario where only insertion and
searching is there and no updation is there in system
then will RAC Interconnect become botteleneck just
for hearbeat messanging.
The Interconnect need not be a bottleneck. Besides, the Interconnect is a fundamental cog in the share-everything cluster machine. It is not a "Bad Thing". So I question what HP is saying - for me to accept such advice, it needs to be backed up with hard technical facts.
If Interconnect is such an issue according to HP, just what do they recommend you use to scale your system with? Let me guess - some very expensive and very complex HP product? A superdome perhaps?
> 3.Indexing time is much more even we create index for
one hour data at one shot, can we dedicate few nodes
in RAC just for indexing.
That is what I'm doing - running up to a 100+ PQ process to do the index builds and rebuilds.
> 4.When i use Create table as select command to
transfer same amount of data from one table to
another table then it takes only 30 seconds and when
i use direct path uploading then it takes 3 minute,
Make sure that you're performance comparisons are valid. What do you imply with "direct path uploading"?
Remember that CTAS is disk-to-disk I/O via the SGA buffer cache. There is no "client side" involved. Nothing external. Not even a PGA buffer area. No pushing data from a client process via IPC to an Oracle server process.
If your benchmark includes pushing data from a client, even from a PL/SQL process, that will be slower than a CTAS - always.
When dealing with such large volumes, the "traditional RDBMS" approach need to be carefully considered. Every single constraint, every single index, every single trigger, results in a tiny overhead that becomes a very huge overhead given the data volumes.
Data management also plays a crucial role. Unless you can manage the data, you cannot effectively insert such huge volumes, process those volumes and query those volumes.
I see RAC and partitioning and PL/SQL server side processing as crucial ingredients to make this work.

Primary database is RAC and Physical standby is single instance

Hello All,
I am using Oracle RAC 11.2.0.3 as primary database, we are going to start using Oracle data guard.
So I am designing my infrastructure and planing to use Oracle 11.2.0.3 Single instance as my physical stand by database.
My question is it feasible to have my standby database as single instance while the primary is RAC?
is it feasible to build my Oracle single instance standby database from the RMAN backup of the RAC primary database?
Is there any restrictions (or any points to be taken into consideration) since my primary database is RAC while the physical standby is Oracle single instance?
in the below link
[http://docs.oracle.com/cd/B28359_01/server.111/b28294/concepts.htm#i1039416]
it was mentioned that primary can be RAC or single and same for standby, but my question is it feasible to have primary as RAC while standby as single instance? or it should be like each others?
The primary database can be either a single-instance Oracle database or an Oracle Real Application Clusters (RAC) database.
Similar to a primary database, a standby database can be either a single-instance Oracle database or an Oracle RAC database.Regards,

My question is it feasible to have my standby database as single instance while the primary is RAC?Yes...quite a common setup.
is it feasible to build my Oracle single instance standby database from the RMAN backup of the RAC primary database?Yes.
Is there any restrictions (or any points to be taken into consideration) since my primary database is RAC while the physical standby is Oracle single instance?No show stoppers.

RMAN + restore rac on single instance...

Hi all,
Can I restore a backup or RAC Database on a single instance?
For example: DB1 is a RAC Database 10.2
I have a RMAN backup of DB1 on host A, copy all files to host B on same directory structure.
Can I restore this backup ??
If someone have any documentation or link, i apreciate too much.
Thanks

Yes, you can. Follow the scenario 'restore the database to a different host'. Be aware you'll need BOTH archive threads!!!
Sybrand Bakker
Senior Oracle DBA

Restoring RAC database to single instance

We run a 2-node RAC instance on 11g (Standard Edition) under SuSE 10 but our remote disaster recovery machine just runs a single instance.
Is it possible to restore from RMAN in this case and how should we go about it?
Thanks!

It is always possible to restore a RAC database backup to single instance. Infact restores are generally made to a single instance. After the restore we convert the database to RAC with required number of instances. Depending on the procedure you use the steps vary.
-Ravi

Oracle RAC on Solarais Configuration Issue

Hi,
We are trying to install Oracle RAC 10g R2 on Solaris 10.
Following are the products
1=> Soalris 10 OS
2=> Sun Cluster 3.1
3=> Veritas Volume Manager
4=> Veritas Cluster File System
Can i deploy Oracle RAC using the above listed Software.
Here we have not purchase any of the Cluster Volume Manager.
Is the CVM required to install Oracle RAC.
Is there any alternative wherein we can install Oracle RAC without using CVM like for example using the RAW device where the VM will manage storage from a single node rather than buying the CVM that will allow to manage the storage from multiple nodes.
Also i would like to highlight is suggestion for using ASM is rule out hence ASM would not be used.
Can anyone suggest me some solution to the above problem.

Well, my impression is that you don't really know what your requirements are and you are trying to fit the technologies somehow. Worse yet, there is no clear understanding how those technologies fit together and as long as you explain what your vendor is saying you (which vendor?) they don't have clear idea either.
I would also suggest to review your decision to use Sun Network Data Replicator for DR site. Consider Oracle Physical Standby database instead - it's more flexible solution and doesn't limit your choice of storage stack.
1) Do Oracle RAC 10gR2 requires any Veritas Cluster Volume Manager
Words "any" and "Veritas" contradict in your question. But the answer is no. RAC require shared storage which can generally be one of those:
- raw devices with or without some kind of cluster volume manager
- cluster file system
- NAS storage (NFS mounted)
- ASM with raw devices for CRS files (OCR and voting disks)
2) Does Oracle RAC 10g R2 require any Vertias Cluster File System or it can sit on normal Vertias File System
Again, Oracle database files MUST reside on shared storage and non-clustered file system is not an option.
3) Is there any solution where we can use the Sun Cluster with Veritas Componets to configure RAC.
If I recall correctly, Sun Cluster includes in it's license some of component of Veritas storage stack. So you might be all set. You should turn to documentation on that stage and see exactly what you have licensed and if your stack allows shared storage. You might want to have a look at http://www.sun.com/software/whitepapers/solaris10/solaris_cluster.pdf
and Oracle Certification Matrix on Metalink.

Adding Box for Oracle RAC(Clustering) to BIW 3.5 Oracle/Linus

Hai Gurus,
Suppose if we have 1 box with Bw3.5 Linux/Oracle and add another box to do Oracle RAC(clustring). Do we need to re-instal the Box 1 also or we can do that with small configuration changes.
Guide me.
Regards,
Mano

Hi Mano
As in most cases there is a short answer and a longer one. Short:
If your system is RAC ready, switching from single instance to cluster database and adding a new node is quite simple. From pure application side there will not be major changes necessary.
Long:
What do i need for oracle RAC, what do i have to do to make my system RAC ready?
Hardware / OS
You will need shared disks, cluster fs, on linux mostly OCFS2. If you don't have it yet, you need to get it and move your database on to it. You would probably need an additional lan interface for the interconnect.
Oracle / Database
You would have to install CRS, that is the oracle cluster software. Your oracle instance, listener will run as services controlled by CRS when RAC is enabled. You will need to configure separate redo threads and undo tablespaces for each node you add. Not least you would probably need an additional costly RAC extension license from your favorite oracle sales rep.
SAP
You should think about separate enqueue server and enqueue replication, although this is not mandatory. This is dependent on your reasons for using RAC. If it is high availability you should go for it.
This is not a complete list, i just wanted to give you an initial idea, please ask if you need further details. If you start into RAC just now, you will have a long way to go, otherwise the short answer will apply.
Best regards
Michael

Does Oracle RAC improve performance over single-instance db

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