You want to back up your 100-GB database on a remote tape device. You are required to ensure
that minimum network bandwidth is consumed while transferring the backups to the tape device.
The current consumption of your CPU is approximately 40 percent.
Which type of backup should you perform?
A.
standard backup set
B.
image copy
C.
compressed backup
D.
user-managed backup
Explanation:
In this scenario, you should use a compressed backup. The size of the database in this scenario is
large, and you are required to reduce the network bandwidth consumed while the backups are
being transferred to a remote tape device. A compressed backup will reduce the size of the
database backup and will eventually reduce the network bandwidth consumed to place the backup
on a remote tape device. The CPU usage in this scenario is low. Therefore, the CPU can tolerate
some overhead that will be generated while compressing backups. You can only perform
compression on backup sets, but not on image copies. Other situations in which compressed
backups can be beneficial are as follows:
– When there is a space constraint on the backup disk.
– When writing backups either to a CD or a DVD– When you want to limit the expense of backup media
You should not use a standard backup set in this scenario because a standard backup set is
larger and will consume more network bandwidth when it is being placed on a remote tape device.
A standard backup set should be used if CPU performance is more important than the benefits
provided by a compressed backup. A compressed backup incurs some CPU overhead and should
not be used if CPU performance cannot be compromised. You cannot use an image copy in this
scenario. You cannot create an image copy on tape devices. An image copy can be created only
on disk. An image copy is an identical copy of a datafile in the database and is created using
RMAN commands. An image copy is larger than a backup set because the unused data blocks
are also copied in an image copy. Image copies should be used when you want to simplify the
recovery process. You should not use user-managed backup in this scenario. The user-managed
backup will be larger than a compressed backup. A user-managed backup creates an exact copy
of a datafile using operating system commands, and copies all the used and unused blocks in the
datafile. This increases the size of the backups. In this scenario, you are required to reduce the
network bandwidth consumed. Therefore, you should choose a backup method that reduces the
size of the backups.