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