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1 Reply Latest reply: Feb 7, 2012 11:37 PM by wzhang RSS

Implications of using DMU with RAC?

clucas-oracle Journeyer
Currently Being Moderated
Neat tool:

I probably missed this but I did not notice any explicit steps for RAC configurations however:
- This inquiiry is due to an email post regarding converting an Exadata database from WE8* to AL32UTF8

Exadata has no impact (it is just an engineered database machine)
however, most all Exadata machines use RAC (heavily) which are commonly 4 up to 8 nodes.

Per previous experience we used to perform the migration on a single node with the other
instances down

a. shutdown the entire RAC database and work with a single node (e.g. Node #1)
b. startup restrict for 'Node#1'
c. perform conversion steps (iDMU objectives: identify, cleanse, convert..etc are much more robust, but still essentially the same outcomes)
d....

Questions
=============

Q1) For RAC would we

d. ...shutdown instance #1 while in restrict to restart with new charset / DD (?)

e. Only then, startup other instances to read the New character set and DD values


Can you please confirm the above as correct or not?


MORE
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Other similar questions on this topic:

Is there a specific note or documentation reference that I missed that might answer the following also?


Q2) Can DMU use a Rolling method for RAC?
- Why or why not
- Do you see this functionality in version x?


Q3) Given the 'high availability' concept of our new engineered systems:
- What is the best practices for maximum availability during charset conversion?
- What is the fastest / suggested method for converting RAC databases where the shortest conversion time is the major factor?

Q4) Do we have a note / case study for RAC + DMU?

Thanks!

Chuck

Edited by: clucas on Feb 7, 2012 8:54 AM
  • 1. Re: Implications of using DMU with RAC?
    wzhang Newbie
    Currently Being Moderated
    Q1) For RAC would we

    d. ...shutdown instance #1 while in restrict to restart with new charset / DD (?)

    e. Only then, startup other instances to read the New character set and DD values


    Can you please confirm the above as correct or not?


    MORE
    --------
    Other similar questions on this topic:

    Is there a specific note or documentation reference that I missed that might answer the following also?
    After the Unicode conversion of instance #1 is completed successfully, you should be able to start up the other instances which will read the new character set information from the updated control files. Instance #1 must be restarted but it doesn't have to be done first.

    >
    Q2) Can DMU use a Rolling method for RAC?
    - Why or why not
    - Do you see this functionality in version x?
    Can you clarify what you mean by a rolling method for RAC? The Unicode migration process converts the character data in a database to Unicode. RAC has multiple instances running on different nodes but they all access a single database.

    >
    Q3) Given the 'high availability' concept of our new engineered systems:
    - What is the best practices for maximum availability during charset conversion?
    - What is the fastest / suggested method for converting RAC databases where the shortest conversion time is the major factor?
    You may want to take a look at [near-zero-downtime migration with DMU and Streams|http://www.oracle.com/technetwork/database/globalization/dmu/learnmore/nzd-migration-524223.html]
    Q4) Do we have a note / case study for RAC + DMU?
    Not at the moment.

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