Oracle Startup Process

Oracle starts up in four states: SHUTDOWN, NOMOUNT, MOUNT, OPEN, and SHUTDOWN. There is no explanation for the first State. All the Oracle files are quietly on the disk, everything hasn't started yet. It belongs to the shutdown status www.2cto.com NOMOUNT status Starting the instance (nomount) * Reading the initialization file from $ ORACLE_HOME/dbs in the following order:-first spfileSID. ora-if not found then, spfile. ora-if not found then, initSID. oraSpecifying the PFILE parameter with STARTUP overrides the default behavior. * Allocating the SGA * Starting the background processes * Opening the alertSID. log file and the trace filesThe database must be named with the DB_NAME parameter either in the initialization Parameter file or in the STARTUP command. -----------------------------------------------------------------------
* Read the parameter file (spfile/pfile) in the dbs directory of the environment variable) [ora10 @ localhost dbs] $ pwd/ora10/product/10.2.0/db_1/dbs [ora10 @ localhost dbs] $ ll-rw-r ----- 1 ora10 dba 3584 07-19 07 spfilechongshi. ora-rw-r ----- 1 ora10 dba 3584 07-23 spfile. ora-rw-r -- 1 ora10 dba 1106 07-19 initchongshi. ora looks for the order of parameter files, as shown in the preceding list. The read priority is spfilechongshi. ora> spfile. ora> initchongshi. ora fails to start if none of the three files are found. * Start the algorithm and allocate the memory www.2cto.com * Start the background process * Open the alertSID. log File and tracking File
[Ora10 @ localhost dbs] $ sqlplus SQL * Plus: Release 10.2.0.1.0-Production on Tue Jul 24 22:33:54 2012 Copyright (c) 1982,200 5, Oracle. all rights reserved. enter user-name:/as sysdbaConnected to an idle instance. SQL> startup nomount; ORACLE instance started. total System Global Area 205520896 bytesFixed Size 1218532 bytesVariable Size 79693852 bytes Database Buffers 121634816 bytes Redo Buffers 297369 6 bytes is now in a nomount state. Mount status Mounting a database has des the following tasks: * Associating a database with a previusly started instance * Locating and opening the control files specified in the parameter file * Reading the control files to obtain the names and status of the data files and online redo log files. however, no checks are saved med to verify the existence of the data files and online redo log files at this time. ------------------------------------------------------------------------------- * associate a database with a started instance * in the parameter file (spfile/pfile), locate the control file and read the parameter file: [ora10 @ localhost dbs] $ strings spfileora10.ora | more ...... *. control_files = '/ora10/product/oradata/ora10/control01.ctl', '/ora10/product/ora data/ora10/control02.ctl ', '/ora10/product/oradata/ora10/control03.ctl '.......
Control File: [ora10 @ localhost ~] $ Cd/ora10/product/oradata/ora10/[ora10 @ localhost ora10] $ ll total 954196 www.2cto.com-rw-r ----- 1 ora10 dba 7061504 07-23 23:01 control01.ctl-rw-r ----- 1 ora10 dba 7061504 07-23 01 control02.ctl-rw-r ----- 1 ora10 dba 7061504 07-23 01 control03.ctl * read the control file, the obtained data files and online redo log files. However, at this time, no check is performed to verify the existing data files and online redo log files [ora10 @ localhost dbs] $ sqlplus SQL * Plus: release 10.2.0.1.0-Production on Tue Jul 24 23:02:28 2012 Copyright (c) 1982,200 5, Oracle. all rights reserved. enter user-name:/as sysdba Connected to an idle instance. SQL> startup mount; ORACLE instance started. total System Global Area 205520896 bytes Fixed Size 1218532 bytes Variable Size 79693852 bytes Database Buffers 121634816 bytes Redo Buffers 2973696 bytes Database mounted.
The Database is now in the mount state. When we start the Database through the mount, the following prompt will be displayed: "Database mounted." The Database is ready. Open state opening the database hosts des the following tasks opening the online data log files opening the onling redo log files If any of the datafiles or noline redo log files are not present when you attempt to open database, the oracle server returns an error. during this final stage, the oracle server verfies that all the data files and online redo log files can be opened and checks the consis Tency of the database. if necessary, the SMON background process initiates instance recovery. when you attempt to open a database, the server returns an error. In this final stage, the server verifies that all data files and online redo log files can be opened and checked for Database Consistency. If necessary, the system monitoring process starts instance recovery. Www.2cto.com: Shut down the database in normal mode. 2. shutdown immediate to immediately shut down the database. Run shutdown immediate in SVRMGRL. The database is not closed immediately. Instead, it is closed after Oracle executes some cleanup tasks (terminate sessions and release session resources). When shutdown is used, the database cannot be closed, shutdown immediate can be used to close a database. 3. shutdown abort closes the database directly, and the session accessing the database is suddenly terminated. If a large number of operations are being performed in the database, it takes a long time to restart the database after the shutdown abort is executed. Author wormhole