RE: Migrating 3TB size database from HP to AIX, also 9i to 10g.

From: "John Hallas" <john.hallas@xxxxxxxxxx>
To: "LS Cheng" <exriscer@xxxxxxxxx>, <Brandon.Allen@xxxxxxxxxxx>
Date: Thu, 20 Sep 2007 10:58:58 +0100

Unquestionable one needs to test any mechanism that will be used for a
large scale migration, especially if under tight time constraints.

I do not doubt that expdp/impdb may perform worse than exp/imp under
certain circumstances but I think it should be the first port of call if
considering that method of data migration.

 

On a large project a couple of years ago we used Shareplex to
trickle-feed changes in to the new system. One outage to export the
original data (8i, Tru64) using multiple parallel exports. Restart
source database with Shareplex capturing changes. 

Build the new empty database (10g, Sun) and import at our leisure (circa
36 hours). 

Multiple schema compares and then apply the captured Shareplex changes.

 

On the night it was "just" a matter of stopping the source database,
letting all the captured changes trickle-feed into the target database
and then making all the DNS/ONS changes to allow connectivity to the new
database.

 

It took about 3 months of effort and a couple of attempts but the above
solution did work.

 

John

 

________________________________

From: LS Cheng [mailto:exriscer@xxxxxxxxx] 
Sent: 20 September 2007 10:39
To: Brandon.Allen@xxxxxxxxxxx
Cc: John Hallas; sjaffarhussain@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: Migrating 3TB size database from HP to AIX, also 9i to 10g.

 

I have not seen DP performance problems...

I have used it to migrate a E-Business Suite database, around 500GB.
With exp it took days, with expdp it took hours. Whem import imp never
ends (well cut off after 4 days) and impdp took around 24 hours. 


Thanks

--
LSC



On 9/19/07, Allen, Brandon <Brandon.Allen@xxxxxxxxxxx> wrote: 

Just a word of caution - I haven't used datapump a lot, but the few
times I have used it I was very disappointed with its performance - it
took MUCH longer than good old exp/imp.  I don't have time to review my
notes right now and give you the specifics of exactly how I ran it with
my timings and all the bugs and tuning notes I found, but just be sure
to do some research first and beware that it's not necessarily true that
datapump speed > exp/imp speed so test it for your specific situation -
as usual, it depends.

Regards,

Brandon

 

________________________________

From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of John Hallas

Once you get to 10g on HP you can use datapump which is much faster

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References:
- Re: Migrating 3TB size database from HP to AIX, also 9i to 10g.
  - From: LS Cheng

RE: Migrating 3TB size database from HP to AIX, also 9i to 10g.

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