Oracle 11gR2 service description

Oracle 11gR2 service description

Some background processes

Background Process	Description
Oracle High Availability Service (OHAS)	OHAS is the first Grid Infrastructure component opened after the server is started. It is configured to open with init (1), and Responsible for generating the agent process.
Oracle Agent	Grid Infrastructure uses two oracle proxy processes. First, in summary, it is responsible for opening some access requests. OCR and VOTING file resources. It is created by OHAS. The second proxy process is created by CRSD and is responsible for opening all resources without the root permission. This process uses The permission of the user to which Grid Infrastructure belongs is run, and is responsible for the work done by racg in RAC11.1.
Oracle Root Agent	Similar to the Oracle proxy process, two Root proxy processes are created. The original proxy process was triggered by OHAS, which Provides initialization for resources in linux that require higher permissions. The main background processes created are CSSD and CRSD. Reverse Here, CRSD will trigger another root proxy. This proxy will open resources that require root permission and primarily related to the network.
Cluster ready service process (CRSD)	The main background process of the cluster software. The oracle cluster registration information is used to manage resources in the cluster.
Cluster Synchronization Service Process (CSSD)	Manage cluster configurations and node members
Oracle Process Monitoring (OPROCD)	Oprocd 11.1 is responsible for I/O isolation. It was introduced to the linux System in the 10.2.0.4 patch set. In this patch The kernel hangcheck-timer module used to perform similar tasks. Interestingly, oprocd was often used in non- Linux platform. Grid Infrastructure replaces the oprocd process with the cssdagent process.
Event manager (EVM)	The EVM is responsible for releasing the Grid Infrastructure creation event.
Cluster Time Synchronization Service (CTSS)	The CTSS service is optional. The Network Time Protocol server provides time synchronization for the cluster. RAC is important. It can run in two modes: wait-and-view or activity. When NTP is activated, it runs in In observation mode, if NTP is not started, it will synchronize all nodes based on the time of the master node.
Oracle Warning Service (ONS)	Major background processes that release events through the quick application framework.