Operation of the Database Client Fault Probe

The database client fault probe performs the following operations:

1. Monitoring the partition for archived redo logs

2. If the partition is healthy, determining whether the database is operational

The probe uses the timeout value that is set in the resource property Probe_timeout to determine how much time to allocate to successfully probe Oracle.

Operations to Monitor the Partition for Archived Redo Logs

The database client fault probe queries the dynamic performance view v$archive_dest to determine all possible destinations for archived redo logs. For every active destination, the probe determines whether the destination is healthy and has sufficient free space for storing archived redo logs.

• If the destination is healthy, the probe determines the amount of free space in the destination's file system. If the amount of free space is less than 10% of the file system's capacity and is less than 20 Mbytes, the probe prints a message to syslog.

• If the destination is in ERROR status, the probe prints a message to syslog and disables operations to determine whether the database is operational. The operations remain disabled until the error condition is cleared .

Operations to Determine Whether the Database is Operational

If the partition for archived redo logs is healthy, the database client fault probe queries the dynamic performance view v$sysstat to obtain database performance statistics. Changes to these statistics indicate that the database is operational. If these statistics remain unchanged between consecutive queries, the fault probe performs database transactions to determine if the database is operational. These transactions involve the creation, updating, and dropping of a table in the user table space.

The database client fault probe performs all its transactions as the Oracle user. The ID of this user is specified during the preparation of the nodes or zones as explained in How to Prepare the Nodes.