B Exadata-Specific Background Processes

The following background processes are part of Oracle Database and Oracle ASM instances in an Exadata environment:

• diskmon Process
  
• XDMG Process
  
• XDWK Process
  

B.1 diskmon Process

The diskmon process is a fundamental component of Oracle Exadata System Software, and is responsible for implementing I/O fencing. The process is located on the database server host computer, and is part of Oracle Clusterware Cluster Ready Services (CRS). This process is important for Oracle Exadata System Software and should not be modified.

The log files for diskmon are located in the $CRS_HOME/log/hostname/diskmon directory.

See Also:

• Oracle Clusterware Administration and Deployment Guide for additional information about the following:

  • Oracle Clusterware Diagnostic and Alert Log Data

  • Overview of Oracle Clusterware Platform-Specific Software Components

• Oracle Database Concepts for information about Oracle Database processes

• Oracle Database Reference for a description of the V$BGPROCESS view that displays information about background processes

B.2 XDMG Process

The XDMG (Exadata Automation Manager) process initiates automation tasks used for monitoring storage. This background process monitors all configured Oracle Exadata Storage Servers for state changes, such as replaced disks, and performs the required tasks for such changes. Its primary task is to watch for inaccessible disks and cells, and to detect when the disks and cells become accessible. When the disks and cells are accessible, the XDMG process initiates the ASM ONLINE process, which is handled by the XDWK background process. The XDMG process runs in the Oracle ASM instances.

B.3 XDWK Process

The XDWK (Exadata Automation Worker) process performs automation tasks by requested by the XDMG background process. The XDWK process begins when asynchronous actions, such as ONLINE, DROP or ADD for an Oracle ASM disk are requested by the XDMG process. The XDWK process stops after 5 minutes of inactivity. The XDWK process runs in the Oracle ASM instances.