Download the ORAchk:
The latest version of ORAchk is attached to Note 1268927.1 and can be downloaded there.

Unzip orachk.zip kit:
$ unzip orachk.zip

You can execute with following commands …
$ ./orachk (for regular healtcheck as well as HA best practices)
$ ./orachk-c hacheck (Only HA best practices)
$./orachk -profile user_defined_checks (user defined checks, checks with their own profile)
$./orachk -excludeprofile user_defined_checks (exclude user defined checks )
$./orachk -c hacheck (only HA best practices)
$./orachk ##provide input for all the requested info, and it generates the health check for databases.

Some ORAchk features:
Proactively scans for the most impactful problems across the various layers of your stack.
Simplifies and streamlines how to investigate and analyze which known issues present a risk to you.
Lightweight tool runs within your environment; no data will be sent to Oracle.
High level reports show your system health risks with the ability to drill down into specific problems and understand their resolutions
Can be configured to send email notifications when it detects problems.
Collection Manager, a companion Application Express web app, provides a single dashboard view of collections across your entire enterprise.

ORACHK report is useful for Oracle support to diagnose issues on your environment. Expertise needed to analyze the reports, and some times difficult in case of bugs.

In case of performance issues, Oracle support needs ORachk, the list of checks:
— Schema changes.
— Log switches.
— Session waits.
— Sysaux usage.
— Stale stats.
— Space consumption
— PGA usage.

and many more.