Taking Oracle9i as an example in Oracle-DBA entry, advanced and diagnostic cases, Oracle10g is used as an example.
1. Oracle Server: instance and database
Instance refers to a group of background processes/threads and a shared memory area. Database refers to a group of physical files stored on the disk. 2. Database startup
Step 1
Nomount status search parameter file pfile/spfile, create an instance, start background process step 2 Mount status step 3 open status start to nomount status # Su-Oracle
View the Alert Log File alert _ <Sid>. log shows the process path for starting this phase/u01/APP/Oracle/admin/ora10g/bdump. You can run the following command in SQL * Plus to check whether the spfile file is used in the database, if the value is not null, the database uses the spfile file: view the background process started from the operating system: When RMAN (recovery manager) is used, oracle allows startup without a parameter file. The database's db_name is named dummy by default;
