* Data Recovery Advisor can diagnose failures such as the following:
/ (B) Components such as datafiles and control files that are not accessible because they do not
exist, do not have the correct access permissions, have been taken offline, and so on
/ (A, E) Physical corruptions such as block checksum failures and invalid block header field values
/ Inconsistencies such as a datafile that is older than other database files
/ I/O failures such as hardware errors, operating system driver failures, and exceeding operating system resource limits (for example, the number of open files)
* The Data Recovery Advisor automatically diagnoses corruption or loss of persistent data on disk, determines the appropriate repair options, and executes repairs at the user's request. This reduces the complexity of recovery process, thereby reducing the Mean Time To Recover (MTTR).

incorrect:
Not A:To create a bigfile tablespace, specify the BIGFILE keyword of the CREATE
TABLESPACE statement (CREATE BIGFILE TABLESPACE ...). Oracle Database
automatically creates a locally managed tablespace with automatic segment space
management.
You can specify SIZE in kilobytes (K), megabytes (M), gigabytes (G), or terabytes (T).
Not D:Although automatic segment space management is the default for all new
permanent, locally managed tablespaces, you can explicitly enable it with the SEGMENT
SPACE MANAGEMENT AUTO clause.

The triggers cloned to the interim table are disabled until the redefinition is completed. Once the redefinition is complete, all cloned objects are renamed to the original names used by they objects they were cloned from.
Ref: http://www.oracle-base.com/articles/10g/online-table-redefinition-enhancements-10gr1.php

HCC requires the use of Oracle Storage - Exadata (A), Pillar Axiom (G) or Sun ZFS Storage Appliance (ZFSSA).
Note:
*Hybrid Columnar Compression, initially only available on Exadata, has been extended to support Pillar Axiom and Sun ZFS Storage Appliance (ZFSSA) storage when used with Oracle Database Enterprise Edition 11.2.0.3 and above
*Oracle offers the ability to manage NFS using a feature called Oracle Direct NFS (dNFS). Oracle Direct NFS implements NFS V3 protocol within the Oracle database kernel itself. Oracle Direct NFS client overcomes many of the challenges associated with using NFS with the Oracle Database with simple configuration, better performance than traditional NFS clients, and offers consistent configuration across platforms.

* The SGA_TARGET parameter can be dynamically increased up to the value specified for the SGA_MAX_SIZE parameter, and it can also be reduced.
*Example:
For example, suppose you have an environment with the following configuration:
SGA_MAX_SIZE = 1024M SGA_TARGET = 512M DB_8K_CACHE_SIZE = 128M In this example, the value of SGA_TARGET can be resized up to 1024M and can also be reduced until one or more of the automatically sized components reaches its minimum size. The exact value depends on environmental factors such as the number of CPUs on the system. However, the value of DB_8K_CACHE_SIZE remains fixed at all times at 128M
*DB_8K_CACHE_SIZE
Size of cache for 8K buffers
*For example, consider this configuration:
SGA_TARGET = 512M DB_8K_CACHE_SIZE = 128M In this example, increasing DB_8K_CACHE_SIZE by 16 M to 144M means that the 16M is taken away from the automatically sized components. Likewise, reducing DB_8K_CACHE_SIZE by 16M to 112M means that the 16M is given to the automatically sized components.