Using RHPhelper to Minimize Downtime During Planned Maintenance on Exadata
(Doc ID 2385790.1)
Last updated on APRIL 02, 2019
Applies to:Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database Cloud Service - Version N/A and later
Oracle Database Products > Exadata
The purpose of RHPhelper is to reduce application service blackouts and brownouts from minutes to a few seconds for applications that meet the prerequisites below. The reduction in application impact is because RHPhelper avoids Oracle sessions from waiting for instance recovery to complete when a node is rebooted or shutdown.
This note explains the benefits of RHPhelper, how to obtain, install, configure and use it.
This note is intended for architects and administrators.
RHPhelper is available only for Exadata systems. You must have the following prerequisites for RHPhelper to work:
- Exadata software version 12.1.x or higher
- GI version 18.3, or higher
- RAC with at least 2 nodes
- Database versions 12.1 or higher (versions below 12.1 will not be drained by RHPhelper)
To obtain the benefit of draining sessions with RHPhelper, you must be:
- using services to connect to the database
- the service should have at least one preferred and one available node (or another preferred node)
- an application using a connection pool that is able to receive FAN events from the cluster (such as Oracle UCP for JDBC)
- RHPhelper must be enabled (see section 2.2 below)
RHPhelper is installed with GI version 18.3 or higher. In GI version 18.3 it is disabled by default. In GI version 18.4 or higher it is enabled by default; see section 2.2 below for how to enable or disable it manually.
You must have the above GI version installed and RHPhelper enabled in the domU (in an OVM environment) to have a domU automatically drain its sessions when a dom0 is rebooted (for example when applying an Exadata DB node patch).
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In this Document
|1.0 Purpose and Operation|
|2.0 Service Configuration|
|2.1 Choosing appropriate drain timeout intervals|
|2.2 RHPhelper Attributes|
|2.2.1 SET RHPhelper attributes|
|2.2.2 Query RHPhelper Attributes|
|3.0 Exadata Compute Node Patching|