Oracle 11gR2 clusterware startup sequence

Starting from 1gR2, Oracle introduced init. ohasd and configured it in the/etc/inittab to start and manage clusterware-related resources.

Pre 11R2

/Etc/inittab

H1: 2: respawn:/etc/init. evmd run>/dev/null 2> & 1 </dev/null

H2: 2: respawn:/etc/init.css d fatal>/dev/null 2> & 1 </dev/null

H3: 2: respawn:/etc/init. crsd run>/dev/null 2> & 1 </dev/null

$ Who-r

. Run-level 2 Jan 22 05:49 2 0 S

11R2

/Etc/inittab

H1: 2: respawn:/etc/init. ohasd run>/dev/null 2> & 1 </dev/null

Oracle> who-r

. Run-level 2 Jul 03 07:52 2 0 S

 

Clusterware resources can be roughly divided into four levels. The corresponding startup sequence is as follows:

Start INIT. ohasd by init, and then start the corresponding four processes in sequence.

Level 1: OHASD Spawns:

Cssdagent-Agent responsible for spawning CSSD.
Orarootagent-Agent responsible for managing all root owned ohasd resources.
Oraagent-Agent responsible for managing all oracle owned ohasd resources.
Cssdmonitor-Monitors CSSD and node health (along wth the cssdagent ).
Level 2: OHASD rootagent spawns:

CRSD-Primary daemon responsible for managing cluster resources.
CTSSD-Cluster Time Synchronization Services Daemon
Diskmon
ACFS (ASM Cluster File System) Drivers
Level 2: OHASD oraagent spawns:

MDNSD-Used for DNS lookup
GIPCD-Used for inter-process and inter-node communication
GPNPD-Grid Plug & Play Profile Daemon
EVMD-Event Monitor Daemon
ASM-Resource for monitoring ASM instances
Level 3: CRSD spawns:

Orarootagent-Agent responsible for managing all root owned crsd resources.
Oraagent-Agent responsible for managing all oracle owned crsd resources.
Level 4: CRSD rootagent spawns:

Network resource-To monitor the public network
Scan vip (s)-Single Client Access Name Virtual IPs
Node VIPs-One per node
ACFS Registery-For mounting ASM Cluster File System
Gns vip (optional)-VIP for GNS
Level 4: CRSD oraagent spawns:

ASM Resouce-ASM Instance (s) resource
Diskgroup-Used for managing/monitoring ASM diskgroups.
DB Resource-Used for monitoring and managing the DB and instances
SCAN Listener-Listener for single client access name, listening on SCAN VIP
Listener-Node listener listening on the Node VIP
Services-Used for monitoring and managing services
ONS-Oracle Notification Service
EONS-Enhanced Oracle Notification Service
GSD-For 9i backward compatibility
GNS (optional)-Grid Naming Service-Performs name resolution
Call crsctl status resource-t to view the status of all components.

Reference Document ID 1053147.1