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Oracle 10g vs SQL Server 2008 Disk Space estimate

  • March 30, 2011 at 4:09 pm

    #237735

    I am working on a migration project where we are migrating data from legacy systems (Oracle10g) to SQL Server 2008.

    Example Question to dipict my situation

    If a DB with 200M rows (combining all tables) is utilizing 50Gigs of diskspace for that schema under oracle, if migrated to SQL Server 2008, what would be the disk space SQL Server requires to store the same Data

    Would it be still 50gigs ? Less? more ? if so whats the relation ?

    I am not looking for a fugurative answer to my example question, but I am trying to learn how differently SQL Server stores data on it ? compared to Oracle.

    When I gave the Disk utilization for Oracle Schemas as 678Gigs, our Sys Admin asked me a this question,

    "Well, that data is stored on Oracle , SQL Server might not occupy the same amount of Data, do you know how much SQL Server would occupy ? Is there a corelation between these too ? some kind of function based on which we can estimate ? "

    Any reference to such an explaination would be appreciated.

    Thanks

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  • March 30, 2011 at 6:42 pm

    #1305756

    they are very nearly the same, i believe; after all, the amount of space needed store any given data type(int/number, varchar/varchar2 is the same in both systems, so you are talking about just a tiny bit of storage overhead differences between the two systems.

    we copy sql db's to oracle for testing all the time, and a !gig database in SQL tends to be about the same size in oracle as well; give or take 50 meg.

    there's no way one system can store the same data, in the same data type, in a radically smaller amount of space than the other system.

    Lowell

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  • March 30, 2011 at 7:12 pm

    #1305762

    Lowell (3/30/2011)there's no way one system can store the same data, in the same data type, in a radically smaller amount of space than the other system.

    Not quite true...SQL Server 2008 and above can implement database and page compression to reduce the overall storage requirements.

    But, that will only work if you test out the system and are confident that enabling the compression will not cause performance issues.

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