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Re: Migration

From: Stephane Faroult <>
Date: Sun, 09 Nov 2003 15:09:25 -0800
Message-ID: <>

"A. Teles" wrote:
> Hi List,
> Could someone please help me?
> Assumption situation - Platform migration of Oracle DW on Oracle DB (data
> volume 3.5 TB) from HP-UX to IBM-AIX
> 1.. DB migration; it is correct to use Export/Import technique/method in
> the above assumption?

    No. Would take ages.

> 2.. Witch is the time frame in a worst case for this (how many hours,
> days or weeks!!)?

    With imp? Could really be weeks.

> 3.. It is possible to apply the mentioned technique or some other (witch
> one?) in uptime, totally or partially?

    You must try to do as many things as you can in parallel, running many processes at once. If you can safely take all the network bandwidth without being fired, SQL*Plus COPY on a table-per-table basis. Which means that you have, prior to that, recreated tablespaces, users, etc.

    Other than SQL*Plus COPY (or CTAS across a dblink), you can download to flat files (there are tools for that), ftp, SQL*Loader direct, which assumes you already have recreated empty tables (exp ROWS=N CONSTRAINTS=N can help).  

> 4.. Witches are the main tasks to consider in a planning schedule?

    The great thing is that you need not backup your database. But you must be able to switch back quickly to the old system if anything goes wrong. Be careful with your scripts (NOVALIDATE when reenabling constraints, for instance). Test a lot beforehand. Otherwise it really depends on your operational constraints. For a hospital you can't afford be offline for a long time.

> 5.. Witches are the time frames associated to these tasks?

    Can really vary. Order of magnitude is likely to be several hours in the best of cases IMHO.

Also, it also depends on how much of your data is really active. You may consider quietly moving the 'dead' or archived part of it, and switching later the really active, much smaller set. Logging activity is also something which can be cntemplated for really difficult cases.


Stephane Faroult
Oriole Software
Please see the official ORACLE-L FAQ:
Author: Stephane Faroult

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Received on Sun Nov 09 2003 - 17:09:25 CST

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