Which two are true about sparse griddisks and their use in disk groups on an X5 Exadata Database Machine? 

Answer options:

A. Sparse diskgroups must be created using sparse griddisks.
B. Sparse diskgroups may be created using a combination of sparse and non-sparse griddisks.
C. Sparse diskgroups may not be used for database snapshots.
D. Additional space for a sparse griddisk is allocated as soon as newly written data is stored in the flashcache on a cell.
E. The virtual size of a sparse griddisk may exceed the physical size of the space occupied by the griddisk.

AE

A: A sparse ASM disk group is composed of sparse grid disks. E: Sparse grid disks allocate space as new data is written to the disk, and therefore have a virtual size that can be much larger than the actual physical size. Sparse grid disks can be used to create a sparse disk group to store database files that will use a small portion of their allocated space. Sparse disk groups are especially useful for quickly and efficiently creating database snapshots on Oracle Exadata. Traditional databases can also be created using a sparse disk group. References: http://docs.oracle.com/cd/E80920_01/SAGUG/exadata-storage-server-snapshots.htm#SAGUG-GUID-42945059-13FD-4F6A-B7FA-A1201D16238F http://docs.oracle.com/cd/E80920_01/DBMSO/exadata-whatsnew.htm#DBMSO22120