Installing Oracle 10g RAC on Oracle VM in windows 2008 using openfiler as shared storage

Dear friends those who interested in knowing more about RAC architecture , they need to prepare one RAC system for their study purpose.Here i got some helpful information from you-tube that provides detailed information  about installing Oracle 10g RAC on windows  .
Thanks Mr.Ahmed D.sherif for his nice presentation.  Here in his demonstration he uses Oracle VM as virtual box, windows server 2003 (32bit) as guest operating system , openfiler+Microsoft iscsi  initiator as shared storage ,oracle database and clusterware (10.2.0.1).

But some softwares listed above  are not available for me and i completed the same setup using  windows server 2008 standard edition(64bit) and oracle software (10.2.0.4) (both clusterware and database software).
The youtube link that i followed is given below,
Part1
http://www.youtube.com/watch?v=6BmwrR3Vcpc
Part2
http://www.youtube.com/watch?v=w7foLjbac4c
Part3
http://www.youtube.com/watch?v=BMPd_XAmtdc
Part4
http://www.youtube.com/watch?v=shVTEpyBohI
Part5
http://www.youtube.com/watch?v=shVTEpyBohI

You can fulfill the RAC set up by following  above link . But i hitched in several stage ,and it eat up my valuable time . Here i want to share that experience.

1. You can install Openfiler software by watching the video , during installation you will prompted for root user password. After installation you will get an url for openfiler interface just like
https://192.168.1.141:446 , it will ask for username and password
Here you have to give  'openfiler' as username not 'root'  ,as  i don't know the default password for 'openfiler' user , so i reset the password by 'root' user.

2.You don't need to download microsoft iscsi software  for windows 2008 server , as it comes in built with windows 2008 server  editions.

3. Once you configured shared disk for RAC in openfiler , You  have to configure the disk on each nodes through microsoft-iscsi. After configuring microsoft-iscsi you can see the shard disk has been appeared in 'Disk Management'  window on every node. Each disk should be in 'online' mode.After that you have to partition each disk (here 5) without any file system and drive name. After these stage i struggled a lot , because while cluster-ware installation it did not detect my previously created shared disk.After googling and studying a lot of articles for more than one weeks, i came to know that in windows clusterware does not support partition created as primary .In windows 2008 server ,by default  it creates partition as 'primary' partition .So you have to use diskpart command to create extended partition in windows 2008. So i deleted every partition that i mounted from storage. Then i created extended partition by using diskpart command.
How to use diskpart command 
1. Take command prompt and run diskpart command 
then type 
DISKPART>list disk
it will show all available disks, 
2.Then select the disk that you want to make extended partition by
DISKPART>select disk 1 
3.Then create extended partition on the selected disk  
DISKPART> create partition extended
You have to follow the same step for remaining disk . Once you created extended partition for all allocated disk , you can create logical partition by right clicking  each disk in the  'Disk Management' window.While creating logical drive keep in mind that not to format the disk  drive also not assign any drive letter.  The end result  become 5 logical disk (as per the video) and are ready to recognized by the clusterware software. Once the disks are ready 
you can go ahead with clusterware installation .

Note:- 
In oracle 10g raw devices are used for storing voting disk and ocr , but from 11g onwards you can keep these things in ASM . So here first two raw device are used for voting disk and ocr (both are configured in external redundancy - having only one disk) and remaining three raw devices are used for ASM.
Rest of my installation never stuck in any stage and i competed my two node RAC setup.

Hope it helps somebody those interested in oracle RAC architecture. 
Enjoy the reading :)
  

Different types of Failover mechanism in Oracle

FAILOVER: 
In the context of Oracle Net, failover refers to the mechanism of switching over to an alternate resource when connection to the primary resource gets terminated due to any reason. Connection failure may be broadly categorized as:
Those that occur while making the initial connection. (Connect Time Failover)
Those that occur after a connection has been successfully established. (TAF)

The first category of connection failure can be dealt with comparatively easily. If your attempt to connect to an instance fails, you can make the connection attempt again, but this time to a backup instance. As long as you have backup instances configured, you can continue trying to connect, until a successful connection is established. This process is technically termed as Connect Time Failover.

Connect Time Failover.
The connect time failover feature allows client to connet to another listener if the initial connection to the first listener fails.Multiple listener locations are specified in the client tnsnames.ora file. If a connection attempt to the first listener fails , a connection request to the next listener in the list is attempted .You can acheive this feature by adding Multiple listener addresses within an address list of tnsnames.Here is an example of what a tnsnames.ora file looks like with a connect-time failover enabled.

TNS Parameter for Connect time failover is FAILOVER. Default value of this is ON.
(failover=on) is default for ADDRESS_LISTs and DESCRIPTION_LISTs , so we do not need to explicitly specify this parameter to put it on.

Sample for TNS net service alias for Client Side Connect time Failover :-

myrac_failover =  
(DESCRIPTION =  
 (ADDRESS_LIST =  
 (ADDRESS = (PROTOCOL = TCP)(HOST = rac1-vip)(PORT = 1522))
  (ADDRESS = (PROTOCOL = TCP)(HOST = rac2-vip)(PORT = 1522))  
 )  
 (CONNECT_DATA =  
 (SERVICE_NAME = myrac)  
 )  
 )

Notice the additional entry under the ADDRESS_LIST section. Here two listener are specified .If a connection is unsuccessful  when attempting to connect to the rac1-vip host on port 1521, a connection attempt is made to the rac2-vip host on port 1521 . 

Note:- Entries in the ADDRESS_LIST do not have to be a RAC nodes . The example that i explained here is for two node RAC database. You can also configure connect-time failover with a standby database , so that one of the entries in the list may be a standby database .As long as the defined service(Database) in the ADDRESS_LIST is availabe on the other 
node , client is able to connect to that node.
For example,

failover_norac=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS= (PROTOCOL=TCP) (HOST=prod_db) (PORT=1521))
(ADDRESS= (PROTOCOL=TCP) (HOST=standby_db) (PORT=1521))
(FAILOVER= TRUE)
)
(CONNECT_DATA=
(SERVICE_NAME= orcl)
)
)
The other criteria, of cource , that the address in the list will allow the client to get to the data that is needed by the application. With oracle RAC , we know that data is always the same, as it is the same database. In the case of physical or logical standby database  
whether or not the data is accessible depends upon how these standby database is configured.

Note:- An important issue to be aware of at this point is that Connect Time Failover only works for you, if you are using dynamic registration. 

Transparent application failover (TAF)
Now, let’s look at how TAF works. Unlike connect time failover, which is invoked before the connection is made, TAF comes into play after the connection is made (and then, broken). If the connection is lost while the application is running, Oracle Net will transparently reconnect the application to another instance accessing the same database.

TAF supports two types of failover: SESSION and SELECT. A SESSION failover connection is not over ambitious. It just fails over to a backup instance. All work in progress at that point are irrevocably lost. SELECT failover is more intricate in as much as it enables some type of read only application to failover without losing the work in progress. If a SELECT statement was in progress at the time of the termination of the connection, then as the connection is reestablished to a backup instance, Oracle Net re-executes the SELECT statement and positions the cursor in a manner that the client can seamlessly continue fetching the rows. But that’s about all that TAF has to offer. It doesn’t have any mechanism to recover DML statements that were in progress, when the failure occurred, or even for SELECT statements, you lose global temporary tables, package states and session settings.
TAF supports two failover methods: BASIC and PRECONNECT. In BASIC method, you connect to the backup instance when the primary connection fails. In the PRECONNECT method, you connect to the backup instance at the same time you connect to the primary instance. This has the obvious benefit of having a backup connection available all of the time, thus reducing the time of ‘failover’. But the downside is that you have to pay the extra ‘cost’ in terms of resources spent, of having a backup connection open all the while.
TAF is configured by adding a FAILOVER_MODE parameter to the CONNECT_DATA parameter for a net service name. Below is an example for configuring TAF with two node RAC

Note:-
Specifies a different net service name to be used to establish the backup connection. A backup should be specified when using PRECONNECT to pre-establish connections. Specifying a BACKUP is strongly recommended for BASIC methods; otherwise, reconnection might first attempt the instance that has just failed, adding additional delay until the client reconnects. 
http://oracleinquisitive.blogspot.in/2012/09/transparent-application-failover-taf.html

How load balancing works in oracle ?

Load Balancing
Oracle RAC systems provide two types of load balancing for automatic workload management:
* Server load balancing distributes processing workload among Oracle RAC nodes.
* Client load balancing distributes new connections among Oracle RAC nodes so that no one server is overwhelmed with connection requests. For example, when a connection fails over to another node because of hardware failure, client load balancing ensures that the redirected connection requests are distributed among the other nodes in the RAC.
The primary difference between these two methods is that the former method distributes processing and the latter method distributes connection attempts.Lets look in details

Client side load balancing 
Client side load balancing is determined by configuring the tnsnames.ora with multiple address in the description ,with parameter LOAD_BALANCE=yes (can specify 'ON' also) , as in this example .
myrac =
  (DESCRIPTION =
   (LOAD_BALANCE=ON)
   (ADDRESS = (PROTOCOL = TCP)(HOST = rac1-vip)(PORT = 1521))
   (ADDRESS = (PROTOCOL = TCP)(HOST = rac2-vip)(PORT = 1521))
    (CONNECT_DATA =
     (SERVICE_NAME = myrac)
    )
  )

Client load balancing helps distribute new connections in your environment so that no one server is overwhelmed with connection requests. When client load balancing is enabled, connection attempts are made randomly among RAC nodes. Suppose you have the Oracle RAC environment  with multiple Oracle RAC nodes, A, B, C, and D. Without client load balancing enabled, connection attempts may be front-loaded, meaning that most connection attempts would try Node A first, then Node B, and so on until a connection attempt is successful.This creates a situation where Node A and Node B can become overloaded with connection requests. Thus in client side load balancing the client will randomly pick an address to try ,without regards to the availability of the node or to how heavily loaded the node may be.

Server Load Balancing
Server side load balancing is controlled by two parameters LOCAL_LISTENER and REMOTE_LISTENER.By default LOCAL_LISTENER is set to blank . Setting local_listener parameter is mandatory when using a different port rather than default .LOCAL_LISTENER on each node should point to the listener on that node.Oracle database have the ability to automatically register their 
presence with an existing default listener with the help of pmon , or you must specify the init parameter LOCAL_LISTENER for non default listener .

A remote listener is a listener residing on one computer that redirects connections to a database instance on another computer. Remote listeners are typically used in an Oracle Real Application Clusters (Oracle RAC) environment. You can configure registration to remote listeners, such as in the case of Oracle RAC, for dedicated server or shared server environments. The REMOTE_LISTENER parameter in the spfile should be pointing to a TNSNAMES entry on each server mode, which in turn list the IPs and ports of all available listeners in the cluster. DBCA will set these entries up for you if you use it to create your databases (recommended).

The remote_listener parameter is then set to listeners_myrac in the spfile

*.remote_listener='LISTENERS_MYRAC'

In tnsnames.ora you can see entry like this,

LISTENERS_MYRAC =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac1-vip )(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac2-vip )(PORT = 1521))
  )

There are two types of server-side load balancing: 
Load Based — Server side load balancing redirects connections by default depending on node load. This id default.
Session Based — Session based load balancing takes into account the number of sessions connected to each node and then distributes the connections to balance the number of sessions across the different nodes.

Note:- Use listener_<instance_name> as the alias name for the local listener, and listeners_<servicename> for the remote listener alias.
The way you set the remote listener changed in rac 11.2 , instead of registering with local listener, the database register with SCAN listener.
This approach is similar to above, but the pain of configuring individual nodes/their VIPs in client tnsnames.ora is eliminated. All we need is a Round Robin enabled DNS name resolution and use the SCAN DNS name in the client tnsnames.ora.If you do not use DBCA, you should set the REMOTE_LISTENER database parameter to scan_name:scan_port. 

Server-side load balancing divides the connection load evenly between all available listeners by determining the total number of connections on each listener, and then distributing new user session connection requests to the least loaded listener(s) based on the total number of sessions already connected. While a bit more complex to implement because it requires configuration of multiple listeners, it most definitely helps to even out connections across all available listeners in a database system.

To implement server-side load balancing, at least two listeners must be configured. Also, the REMOTE_LISTENERS initialization parameter must be added to the database’s PFILE or SPFILE so that the database knows to search out the value provided in that parameter in the database server’s TNSNAMES.ORA configuration file. When server-side load balancing is activated, each listener that contributes a listening endpoint communicates with the other listener(s) via each database instance’s PMON process. Oracle then determines how many user connections each listener is servicing, and it will distribute any new connection requests so that the load is balanced evenly across all servers. The entries in TNSNAMES.ORA direct the listeners to share information about the relative load connectivity.