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4 Replies Latest reply: Feb 22, 2013 2:18 PM by user9957 RSS

Data Guard - Keeping same SID/Instance Name across both sites

user9957 Newbie
Currently Being Moderated
Hello,

We are working on a project to move the databases from legacy to new servers. The migration plan is to use Data Guard option for our migration strategy. We would like to know followings.

1) Is it possible to build stand by databases with same instance name of legacy primary instances? If so, how it could be?
2) If not, we can build stand by database with different instance name (DB_UNIQUE_NAME). Do the switch over and cut off the replication with legacy primary database. Once done, What other alternative do we have to change the instance name same like legacy database instances?

The ultimate goal is to retain same DB name and instance name in new server with minimum downtime.

Database - 11.2.0.3.0
Database Type - Oracle restart and RAC
O.S. - RHEL 6.3

The requirement is have same DB name and instance name across sites.

Primary site - X node
Primary DB - EODSS
Primary DB instances - EODSS1, EODSS1

Standby Site - Y node
StandBy DB - EODS
StandBy instances - EODSS1, EODSS1

Thanks,
Pankaj

Edited by: user12025125 on Feb 22, 2013 12:33 PM
  • 1. Re: Data Guard - Keeping same SID/Instance Name across both sites
    mseberg Guru
    Currently Being Moderated
    Hello;

    1) Is it possible to build stand by databases with same instance name of legacy primary instances? If so, how it could be?

    Yes. Not sure I understand the second part of the question. I like to think of a standby database and a primary database as the same database in different modes. RMAN treats them as the same. They have the same DBID.


    2) If not, we can build stand by database with different instance name (DB_UNIQUE_NAME). Do the switch over and cut off the replication with legacy primary database. Once done, What other alternative do we have to change the instance name same like legacy database instances?

    It should not matter what the database name is. Almost everything connects using an Alias. I find it easier to use a slightly different name for the Standby because then I know which site I'm working on. What I did was put an S in front of the name on the standby side to keep them apart in my mind. A tnsnames entry can handle the rest. So yes you can do that, but it might be harder to keep track that way.
    ernie =
     (DESCRIPTION =
        (ADDRESS_LIST =
           (ADDRESS = (PROTOCOL = TCP)(HOST = primary.server)(PORT = 1521))
           (ADDRESS = (PROTOCOL = TCP)(HOST = standby.server)(PORT = 1521))
           )
           (CONNECT_DATA =
           (SERVICE_NAME = ernie)
        )
     )
    Best Regards

    mseberg
  • 2. Re: Data Guard - Keeping same SID/Instance Name across both sites
    user9957 Newbie
    Currently Being Moderated
    Thanks for your quick response. I forgot to explain my complete requirement.

    The plan is to move all the databases from legacy to new servers using Data Guard to minimize the downtime. The name, SID of DG site would be the same like legacy system .Once it will be validated by consumers, we will cut off replication to legacy and later drop the legacy database.

    The reason behind that there are unknown application which connects to database using instance name not DB name and if we don't retain the same name, those will see impact after migration which we don't want.

    Please assist the best way to accomplish this requirement.

    Thanks,
    Pankaj
  • 3. Re: Data Guard - Keeping same SID/Instance Name across both sites
    mseberg Guru
    Currently Being Moderated
    Pankaj;

    OK then just use the name you want. You can use same name.

    DB_NAME should be same.
    DB_UNIQUE_NAME should be different.


    It works either way, nothing special. So I use different so my SID on the primary is PRIMARY and its STANDBY on the standby. You would just use the same SID ( as before ) its as simple as that.

    DB_UNIQUE_NAME attribute is introduced to clearly identify the relationship between a primary and standby databases.

    Also of interest

    Oracle data guard configuration for primary and standby db_name



    Best Regards

    mseberg

    Edited by: mseberg on Feb 22, 2013 3:13 PM
  • 4. Re: Data Guard - Keeping same SID/Instance Name across both sites
    user9957 Newbie
    Currently Being Moderated
    Thanks a lot, It cleared all my doubts.

    Regards,
    Pankaj Gupta

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