Databases Reference
In-Depth Information
Moving a Backup from Disk to Tape
Now that you know the options of backing up to the disk and going to the tape directly, you can combine the two
options to have a two-phase solution: backing up to the disk, and then moving the backup to the tape. This approach
has a number of very attractive benefits:
•
This option represents the best of both worlds: the benefits of disk (regardless of the storage
inside or outside of Exadata) and tape.
•
Since the first backup of the database is to the disk, it allows you to merge the RMAN
incremental backup to the image copy on disk. This feature reduces the need to take full
backups often.
•
Allows you to take advantage of the VTLs (Virtual Tape Libraries), explained above.
•
When recovery is needed, and the on-disk backup is not available, the restore can be
done from tape to the database directly. There is no need to restore to disk first and then
to the database.
•
The dual staged backup approach—(a) DB to Disk and (b) Disk to Tape—makes it possible to
decouple the stages. Stage (a) can be done anytime that is good for the database, while stage
(b) can be made to fit the schedule of the tape facility.
•
You can use the space inside the Exadata rack, which is simpler when backing up to disk.
The risk of putting the backup inside the Exadata rack is mitigated by the eventual presence of
the backup on tape.
The option has some drawbacks.
•
It needs space—on both the disk and the tape.
•
If you used ASM as a location for the disk-based backup, you need to use Media Management
layer (MML) to move the backup to the tape. You can avoid the use of ASM by putting the
disk location on an NFS mount point but it has the same issues described earlier under the
option of NFS.
Backing Up Inside the Exadata Rack
Problem
You want to back up the database on Exadata inside the same rack.
Solution
To back up the database to a space inside the same Exadata rack, you first have to decide on the location of the
backup. You have two choices:
•
In the fast recovery area (FRA) location
•
On a specially created ASM diskgroup
