Application Server Guard, Disaster Recovery for Oracle Application Server

Application Server Guard is Next level of Disaster Recovery Solution by Oracle (Currently only for Application Server/ Fusion Middleware). Application Server Guard (with underlying dataguard for database) incorporate Middle Tier configuration recovery on standby site.
Lets discover overview & main component of AS Guard ( ASG , also called as DSA Distributed Server Architecture).

Components of AS Guard
Application Server Guard also called as AS Guard is automatically Installed with 10g Application Server . Real features/advantages of AS Guard started with version 10.1.2.0.2 and bugs associated in this release with some more features are fixed in Version 10.1.2.2.0 . AS Guard binaries are Installed under folder “DSA” under oracle_home . If you have standalone database , you can install standalone AS Guard under database oracle_home. Software is available at Here, Click here to download

AS Guard consist of Server & client (any ASGuard with asgctl.sh can act as Client).

For database it uses dataguard (You don’t have to configured dataguard for database AS Guard will configure it for you if your database was part of Application Server Installation) If your database is created by MRCA/Repca (Metadata Repository Creation Assistance Tool) then you have to configure Dataguard at your own.

For Identity Management & Middle tier configuration it uses backup & recovery tool in Application Server (This is automated by AS Guard, you don’t have to do anything)

Primary & Standby Site
Primary & Standby site can be synchronous (Same number of nodes in standby as primary) or asynchronous (Number of nodes in standby are less as compared to primary-Like primary site is with two middle tier and one infra tier where as standby site with only one middle tier & one infra tier- P.S. standby site should have at least one middle tier & one infrastructure tier)

Start/Stop AS Guard Server
If AS Guard Server is part of application Server you start it using opmnctl like
opmnctl startproc ias-component=DSA
For standalone AS Guard you use dsaServer.sh under oracle_home/dsa/bin like
nohup dsaServer.sh &

Operations in AS Guard

Instantiate
This is process of building primary & standby relationship and done only once. In this step AS Guard will create standby database for Application Server metadata repository database , backup configuration files from primary site & restore them to standby site

Sync-
This is method of synching standby site with primary site. In this step standby database is synched with primary database . Configuration files from IM node & middle tier node on primary site are backed up & restored in standby site

Switchover-
This is the process of converting role of primary in to standby & standby into primary. Useful in situation like server maintenance in primary site or any activity on primary site so that standby site can be used as primary site

Failover-
This is the process of converting standby site as primary (same as above except here primary site is not converted as standby). Useful in situation if primary site is not available because of some reason.

For using AS Guard (Application Server Guard) as Disaster Recovery solution , you have to select HA (High Availability) & then Virtual Host during IM Installation.

More on AS Guard configuration coming soon….

About the Author Atul Kumar

Oracle ACE, Author, Speaker and Founder of K21 Technologies & K21 Academy : Specialising in Design, Implement, and Trainings.

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32 comments
Anonymous says December 3, 2006

Nice as always, i was wondering if you can post something related to High availability on application server (web or forms) server if its doable and how can we get there.

thanks and keep up the good work

fadi hasweh
http://oracle-magic.blogspot.com/
Oracle is not Magic, it just takes years of experience

Reply
Atul Kumar says December 3, 2006

Yes Fadi, It can be achieved by configuring multiple middle tiers front ended by Load balancer .

Atul

Reply
falah says December 7, 2006

superb doc.
i had one query. can i use the clone command instead of installing the standby software (infra and mid tier).

If yes then before performing the clone what are the software need to install on standby machine.

regards

falahuddin

Reply
falah says December 7, 2006

superb doc.
i had one query. can i use the clone command instead of installing the standby software (infra and mid tier).

If yes then before performing the clone what are the software need to install on standby machine.

regards

falahuddin

Reply
Atul Kumar says December 7, 2006

falahuddin
Thanks a lot for your compliments .
You can clone Middle Tier on standby site (For Infra Node I need to check if you can clone by AS Guard)

You need to install standalone AS Guard in standby site (under oracle_home, though there won’t be any files in that oracle_home apart from as guard before cloning)

Atul

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Anonymous says December 7, 2006

Thanks for quick reply

another query which will be helpful to all.

Does this agctl command we have to run from infra (primay) at the time of setup or from any other home.

Further for sync,agctl utility has to be run from primary site (any home).

thanks..
falah

Reply
Anonymous says December 18, 2006

Hi ,

I am glad to inform that I have done the initial step for configuring the AS Guard.

Further I need some clarification.

Let me give u the following details

linux box1.(primary)

Ip 192.168.1.1 – infra.abc.com – IDM +db is installed
Ip 192.168.1.1 – app.abc.com – midtier is installed
etc/host- entries- the above two and Ip 192.168.1.2 – remoteinfra.abc.com – (IDM +db) of standby server

linux box2.(standby)

Ip 192.168.1.2 – infra.abc.com – IDM +db is installed
Ip 192.168.1.2 – app.abc.com – midtier is installed
etc/host- entries- the above two and Ip 192.168.1.2 – remoteinfra.abc.com – (IDM +db) of primary server

DSA server is started on all the four boxes.

when i start the asgctl.sh on primary box in infra home and executed the following commands

ASGCTL> connect asg infra ias_admin/infra123
Successfully connected to infraha:7890
ASGCTL>
ASGCTL>
ASGCTL> discover topology oidpasswd=infra123

Discovering topology on host “infra” with IP address “192.168.1.1”

ohsarch:7890
Connecting to the OID server on host “infra.abc.com” using SSL port “636” and username “orcladmin”
Getting the list of databases from OID
Gathering database information for SID “dbinfra” from host ” infra.abc.com”
Getting the list of instances from OID
Gathering instance information for “infra_home.infra.abc.com” from host “infra.abc.com”
Gathering instance information for “app_home.app.abc.com” from host “ohsarch.idc.oracle.com”
********** WARNING **********
app: –>ASG_IAS-15779: Error getting instance information for instance “app_home.app.abc.com” from host “app.abc.com”. This instance will be excluded from the topology.xml file
app: –>ASG_IAS-15632: The home that contains instance “app_home.app.abc.com” could not be found
******** END WARNING ********
The topology has been discovered. A topology.xml file has been written to each home in the topology.

ASGCTL>

SGCTL> verify topology with remoteinfraha
Generating default policy for this operation

app:7890
HA directory exists for instance infra_home.infra.abc.com
HA directory exists for instance infra_home.infra.abc.com
Verifying that the topology is symmetrical in both primary and standby configuration
ASGCTL>

Question 1 :-

1- If we are installing the infra and app on same server, Is it mandatory use Virtual I P for tier
2- what is the reason of getting the two warnings ASG_IAS-15779 – is this normal..
3- can i now start the instantiate command after setting the primary database.

Can suggest some replies to the above query it would be very helpful.

Regards

Falahuddin

Reply
Atul Kumar says December 18, 2006

Falah,
Congratulations !!

1- If we are installing the infra and app on same server, Is it mandatory use Virtual I P for tier

Yes, It is mandatory to use Virtual IP for Infrastructure Tier Installation

2- what is the reason of getting the two warnings ASG_IAS-15779 – is this normal..

No this is not normal, It seems DSA server on Middle Tier is down

start it using

opmnctl startproc ias-component=DSA

Try again & let me know results

3- can i now start the instantiate command after setting the primary database.

Yes, Just start Middle tier DSA using command mentioned above & then set database & then Intantiate

Reply
Anonymous says December 18, 2006

Hi,

Thanks for responding very quickly.

All four DSA component on two servers are started the following is the result of the opmnctl status command.
DSA | DSA | 32439 | Alive

Further i would like to know whether the above error is the result of not using the Virtual IP

can u suggest me what should i do further.

thanks

falah

Reply
Atul Kumar says December 18, 2006

Falah,

You don’t have to use Virtual Host on Middle Tier .

What is ohsarch.idc.oracle.com ? (Is this the actual host name of machine on which you installed i.e. 192.168.1.1)

If both Middle Tier & Infra Tier are on same host what is DSA port for middle tier (I suppose it would be 7891 )

Check
“netstat -an | grep $port_no” on middle tier

All check log files at $ORACLE_HOME/dsa/logs/duf_server.log

Please use http://teachMeOracle.com/forum to discuss further & mention all details there

Reply
Anonymous says December 18, 2006

Hi,

i have not use the virtual hostname for midtier.. app.abc.com is the hostname.. regarding the name u r referring that has come by mistake..

hostname = app.abc.com

And i accessed the site by http://app.abc.com:7778..
port for infra = 7890
port for midtier =7891

checked the two log files, but there i cannot find anything related to this.

regards
falah

Reply
Atul Kumar says December 18, 2006

Falah,
Name “ohsarch.idc.oracle.com” cannot come into OID by mistake , Check topology.xml file at $OH/dsa/conf

When you installed services on app.abc.com was there any entry for ohsarch.idc.oracle.com (Oracle Hosted Services Architecture Team 😉 , I used to work in past) in /etc/hosts or for servername ?

execute discover topology again & check in topology.xml at $OH/dsa/conf what all server names its registering ?

Reply
Anonymous says December 19, 2006

As i explained u earlier..

The hostname for midtier is app.abc.com while writing u the comment i think i made mistake.

Is the above problem due to orainventory or what .. i am using the same orainventory location for infra and apps.

while executing the Discover command in apps home ..it is not able to find the oracle home for infra.

i checked all log but no use.
All the DSA components are alive.

regards

falah

Reply
Atul Kumar says December 19, 2006

Falah,
Your AS Guard is not able to retrieve Middle Tier Instance Information .

You need to enable tracing but I am nit going to explain that here , Please use Forum for Discussing issues .

http://teachMeOracle.com/forum

Atul

Reply
Anonymous says December 19, 2006

Thanks,,

my login id is not working for teachmeoracle, that is the reason i am not using the forum

Anyways thanks for help

Regards

falah

Reply
Anonymous says December 20, 2006

Hi,

i had raised my queries at teachmeoracle forum for appilication server – As guard.

Can u pls help in solving the issue.

Regards

falah

Reply
Atul Kumar says December 20, 2006

Falah,
I’ll get back to you on Forum at http://teachMeOracle.com/forum

Reply
Anonymous says January 18, 2007

Hi Atul,

I am regular reader of your site.
I am planing to install a DR site (standby site)using 10gAS guard and 10g data guard.If you have installed earlier could you publish your notes please.

Thanks,

SAT

Reply
Atul Kumar says January 18, 2007

SAT,
Yes I have done DR for 10g AS using AS Guard which includes Data Guard but to put it all on net is big tedious (I have all docs & steps but need to put them in right doc)

I’ll try to prepare one by end on this month (31-Jan-07). I’ll update it in posting once done . So stay tuned ….

Reply
Anonymous says January 18, 2007

Hi Atul,

Thanks for this.
There are few questions in my mind, could you please answers these :-
1.Out production site is up and runing for the last 1 years , so what all we need to set up DR site?
2. What about Infra’s database , do we need to use database (i suppose not as you said earlier ).

Regards,

SAT

Reply
Anonymous says January 18, 2007

Hi Atul,

pleaes read my second point as … do we need to use dataguard.

Apologies for typo mistake.

Thanks,

SAT

Reply
Atul Kumar says January 18, 2007

SAT,
Supported & Certified way of DR for Application Server is AS Guard.

When you configure AS Guard AS gaurd will automatically configure Datagaurd for Infrastructure database (If this is installed as per standrad Installation) . If this database is configured by MRCA or Repca then you have to configure Data Guard for database before configuring AS Guard.

1.Out production site is up and runing for the last 1 years , so what all we need to set up DR site?
You have to create another site (with atleast one Middle Tier Home & 1 Infra Home) and then use asgctl utility to configure AS Guard between them .

Reply
Anonymous says January 18, 2007

Hi Atul,

Thanks for update.
Few more questions :-

1.We are on the 10g AS 10.1.2.0.0 , so do we need to update AS to use server guard ?
2.Will there any data difference on primary and standby database i.e. delay in log shipping etc.

Thanks in advance,

SAT

Reply
Atul Kumar says January 18, 2007

In 10.1.2.0.0 AS Guard is Installed by default but not started .

opmnctl startproc ias-component=DSA

(DSA server is called as AS Guard , default port is 7890)

You need to do additional steps for AS Guard apart from simply starting it.

2.Will there any data difference on primary and standby database i.e. delay in log shipping etc.

This you can control depending on your requirement .

For Any Issues / doubts raise it in forum at http://teachmeoracle.com/forum under HA Section in Application Server

Reply
Anonymous says January 18, 2007

Hi Atul,

Great stuff….

Lastly ,on the standy site we if we are installing infra then by default a database will be created for infra tier, so my query is what to do with this database i mean do we need to remove this datbase or what will happen when AS guard will try to create standy database on ifra tier?

Thanks in advance,

SAT

Reply
Atul Kumar says January 18, 2007

SAT,
This is my last reply here for your doubts on AS Guard 🙂 (I love to clear your doubts but right place is Forum for that).

When you Install Infra Tier on DR it will Install database as well.

Once you run Instantiate command to link standby site with primary , AS Guard will covert primary database in Archive mode ; shutdown primary database ; copy datafiles from primary to standby (automatically delete original datafiles from standby site database) ; start primary database ; start standby database in standby mode. So you don’t have to do any thing .

I hope this is clear 🙂 If not kindly raise further doubt in Forum at http://teachMeOracle.com/forum & I’ll get back to you .

Cheers

Reply
Anonymous says January 18, 2007

Cheers Atul,

Thanks for your all effort.
I will raise my issues in proper forum.

Thanks,

SAT

Reply
Elizabeth says July 14, 2009

Hi Atul

Do you have a document to configure Disaster recovery from scratch by cloning method.

regards

Reply
Atul Kumar says July 14, 2009

@ Elizabeth , For 11i or R12 configuration with Dataguard use below metalink notes
452056.1 Business Continuity for Oracle Applications Release 12 on Database Release 10gR2 – Single Instance and RAC
753241.1 Case Study : Configuring Standby Database(Dataguard) on R12 using RMAN Hot Backup

216212.1 – Business Continuity for Oracle Applications Release 11i, Database Releases 9i and 10g
341437.1 – Business Continuity for Oracle Applications 11i Using RAC and Physical Standby
403347.1 Maximum Availability Architecture and Oracle E-Business Suite Release 11i

Dataguard Concepts – http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/concepts.htm#i1039416

Reply
anand says October 6, 2009

Hi Atul,
This is a good explanative doc:).I have a small doubt.I did not install High Availability and Replication at the time of IM installation.So is it possible for me to go ahead implementing Guard?
Can I install ASG 10.1.2.2 directly in th oracle_home and check if it works…

Reply
Atul Kumar says October 6, 2009

@ Anad,
If You this is new implementation then don’t go for Application Server Guard (Oracle Statement of direction for HA on middleware is to use datagaurd for database and disk replication technology like rsynch for middle tier )

For configuration on application guard, I think you can still configure ASGuard in existing ORACLE_HOME (by default ASGuard is installed but not configured so configure it)

Only limitation is to keep hostname on primary and standby site same.

Reply
anand says October 7, 2009

Hey Atul thanx for replying :).It’s true regarding Oracle’s Statement of direction for HA on middleware.I dont know why Oracle wants ASGuard to be stopped now.Is it not better anymore than rsync etc..

My OAS is 10g R2 10.1.2.0.2.I want a lil confirmation that I can actually go ahead installing ASG 10.1.2.2 in both my oracle_home’s (10.1.2.0.2) and try setting up Guard.

I will check with Rsync like you suggested if that is better than ASGuard.:)thanx

Reply
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