Raw Partitions and Windows NT

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1.0  What is a Raw Partition?

2.0  When to use Raw Partitions  

         2.1 I/O Bound Application  

         2.2 Oracle Parallel Server  

         2.3 Asynchronous I/O (Overlapped I/O)

3.0  Advantages and drawbacks of Raw Partitions compared to File Systems

         3.1 Advantages

         3.2 Drawbacks 

4.0  Setting Up   

         4.1 Calculating The Size of the Partition  

         4.2 Creating the partitions  

         4.3 Specifying in a create tablespace command  

         4.4 Symbolic Links       

                 A) Creating Symbolic Links

                 B) Removing Symbolic Links

5.0  Backup Strategies   

         5.1 OCOPY80.EXE

         5.2 RMAN

6.0  Raw Devices and Export/Import

7.0  How to switch files from a File System to Raw Device or from a Raw

     Device to a File System.

8.0  Remarks

1.0  What is a Raw Partition?

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Raw partitions or devices are disk partitions that are not mounted and written 

to as a file system, but are accessed via a character device driver.  It is the 

responsibility of the application to organize how the data is written to the 

disk partition.  So a Raw Partition is a segment of disk space pointed by the 

partition table.  There is no file system out there, no directories (no DIR or 

NT Explorer).

Disk Naming

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At startup, Windows NT names each found disk drives following this naming

convention:

     DeviceHarddiskPartition

     where:  :  the number of the physical drive - starts with 0

             :  the number of the logical number as show in the NT Disk 

                   Adminstrator - starts with 1

     DeviceHarddisk0Partition1 would typically be the C drive

Raw Partition Definition

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There are two different types (definition methods) of Raw Partitions

      a) physical disk 

      b) logical disk 

TIP:

Although you actualy could you the physical disk approach, its 

strongly recommended to use the logical disk approach.

a)  Physical disk:

    A physical disk or Partition0 actualy refers to the whole disk

       DeviceHarddiskPartition0

    When using the Setlinks command on a Dos prompt you will notice that Windows

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