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Load balancing with Oracle RAC [message #133683]

Sun, 21 August 2005 11:08

jef1
Messages: 6
Registered: June 2005

Junior Member

Hello,
for the moment i don't know a lot about capabilities provided by Oracle RAC server option but for I'm interested in it. I would like to know how does the load balancing work with this technology ? If 3 Oracle instances for example are built,configured and started on 3 physical servers how will the requests from a client application be serviced ? Is it necessary to configure and start a process manager on a dedicated server which will route the client requests to the best node for processing ? What does the application see and what are the informations mandatory to connect to the Oracle cluster ? Is there a tradeoff to choose between response time given to end users and high availability ?
If you have responses to these questions or documentation that can be useful to understand these concepts !
Thanks a lot for your help.

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Re: Load balancing with Oracle RAC [message #133788 is a reply to message #133683]

Mon, 22 August 2005 04:33

Frank Naude
Messages: 4581
Registered: April 1998

Senior Member

Hi,

Load balancing is documented in the Net Services Manuals, which is why most people working with RAC have problems finding it. In summary:

To enable Load balancing, you need to use a TNSNAMES.ORA entry like this:

net_service_name =
 (DESCRIPTION= 
  (LOAD_BALANCE=on)
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales1-svr)(PORT=1521))
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales2-svr)(PORT=1521)))
  (CONNECT_DATA=(SERVICE_NAME=sales.us.acme.com))

On the RAC side, you need to specify a REMOTE_LSITENER so all instances register their load characteristics with all listeners. A listener can then decide if it wants to accept a connection or hand-over to a less loaded listener.

Best regards.

Frank

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Re: Load balancing with Oracle RAC [message #140914 is a reply to message #133788]

Thu, 06 October 2005 03:28

phanikrishna9
Messages: 4
Registered: October 2005
Location: Hyderabad

Junior Member

Dear Frank,

I agree with you in configuring Load Balancing.

but in my case, I want to monitor the load on each of the Nodes. So that I can recommend Hardware upgradations or swap space upgradations.

Also I want to monitor the Load on Each of the nodes.

Pls help

Thanks and Regards

Phani.

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Re: Load balancing with Oracle RAC [message #140984 is a reply to message #140914]

Thu, 06 October 2005 08:32

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

Did you look into AWR?
Automatic workload repository stores work load information per instance.

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Re: Load balancing with Oracle RAC [message #141107 is a reply to message #140984]

Fri, 07 October 2005 00:00

phanikrishna9
Messages: 4
Registered: October 2005
Location: Hyderabad

Junior Member

Thanks Vivek,

However, I prepared the following Checklist to be done a Daily Basis. Please help me improvise the list.

This is basically a checklist to Check after implementing a RAC. I feel this needs to be checked daily:

1) Transparent Application Failovers
2) RAC Interconnect waits
Buffer busy global cr
Global cache busy
Buffer busy global cache
3) Objects that are causing contention in RAC.
4) RAC Cluster Interconnect Timings:LMS SERVICE TIME
5) RAC Global Cache Blocks Lost/Corrupted
6) RAC Cluster Interconnect Current Block Service Time Statistics
7) Locks &Latches Contention
Cool

Global cache hit ratio
9) Throughput
10) SGA Parameters Instance Level
11) Global Services Daemon Error messages(Or) Cluster command Errors(Or) Server Control Utility errors.
12) Any of the following errors:
( ORA-600/4031/29702/12541)
13) Memory Utilization.
14) cpu Utilization.
15)Alert logs for all instances
16) Ratio of fusion vs physical writes
17) Buffer Busy waits per second.
18) OS Cluster Verfication

Ur comments r appreciated.

Thanks

Phani Krishna.

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Re: Load balancing with Oracle RAC [message #141181 is a reply to message #141107]

Fri, 07 October 2005 07:10

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

The RAC instances need to monitored/tuned/adminstered in the same method as a regular single instance (99% the same).
There is no difference at all. You need to lookinto something additional that is specific for RAC only in certain cases. Thats it.
And forget about buffer cache hit ratios. It is meaningless.
All the rest ( alert logs,ora-600 etc) are generic for all oralce databases.

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