9.4 Sparse Disk Sizing and Allocation Methodology

To create Exadata Snapshots, you must have sparse grid disks created with an Oracle ASM disk group created based on those disks.

It is not possible to directly modify an existing disk group and convert it into a sparse disk group; you must create the grid disks with the sparse attributes. If you want to use an existing disk group, then the disk group and associated grid disks must be dropped and re-created.

If you want to create a new sparse disk group and all of your space is currently allocated to existing disk groups, then you must resize one or more existing disk groups to free up space. Use the following steps to perform this process.

• Sizing Steps for New Sparse Disk Groups
  These steps describe how to determine the space needed for sparse disk groups and how to allocate that space.