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  1. #1
    Join Date
    Nov 2005
    Posts
    24

    Unanswered: DMS containers.........

    Hi,

    Is a file expensive or a device, for a DMS tablespace?
    Is there any other advantage for using device other than to by pass the file system cache?

    Please help.

    Thanks,
    Db

  2. #2
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650
    In strict sense, using a device is a better option than using a file container .. But with today's advancements in storage technology, the difference is not big ... It is much more difficult to configure and manage device based DMS containers ... Therefore, the general recommendation is to use file containers ...

    If you are on Windows , you may use the DB2NTNOCACHE registry variable for both SMS and DMS ..

    If you are on V8.1.4 and above on AIX 5.2 (check the documentation for more detailed patch information), limited direct i/o support is available for SMS tablespaces but hopefully may get extended to DMS file containers sometime soon ...

    Cheers
    Sathyaram

    Quote Originally Posted by db1db2
    Hi,

    Is a file expensive or a device, for a DMS tablespace?
    Is there any other advantage for using device other than to by pass the file system cache?

    Please help.

    Thanks,
    Db
    Visit the new-look IDUG Website , register to gain access to the excellent content.

  3. #3
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    It also depends on the nature of the application. If you have a data warehouse with a lot of table scans of the entire table, then devices have a slight advantage. Otherwise you will see very little or no increase in performance compared to using a file system.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

  4. #4
    Join Date
    Nov 2005
    Posts
    24
    Thanks a lot for the information.

    -Db

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