The Control File can be considered to be the most important file in a database, it is the identity of the database.<\/p>\n
Every database instance has at least 1 control file, the recommended practice is to have at least 2 control files located on separate physical disks. 3 control files are created by default.<\/p>\n
The contents of a database’s Control File include:<\/p>\n
\u2022 The names and locations (paths) of Data Files<\/p>\n
\u2022 The names and locations of Redo Logs<\/p>\n
\u2022 Current Log sequence numbers<\/p>\n
\u2022 Backup Set information<\/p>\n
& most importantly<\/p>\n
\u2022 System Change Number (SCN) information<\/p>\n
<\/p>\n
Users cannot view or alter a Control File as it is in binary format.<\/p>\n
<\/p>\n
Control Files can be copied in two ways.<\/p>\n
1. While the database is open<\/strong><\/p>\n If a Control File’s location hasn’t been specified while creating the database, all 3 control files will be in the same path (\/u01\/app\/oracle\/oradata\/SID_NAME\/<\/strong>) ‘\/u01\/app\/oracle\/oradata\/smp\/control02.ctl’,<\/p>\n ‘\/u01\/app\/oracle\/oradata\/smp\/control03.ctl’,<\/p>\n ‘\/u02\/IndexData\/smp\/control04.ctl’ scope=spfile; [crayon] [crayon] [crayon] Checking the validity of the changes that have been made:<\/p>\n [crayon] NAME<\/p>\n ——————————————————————————–<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control01.ctl<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control02.ctl<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control03.ctl<\/p>\n \/u02\/IndexData\/smp\/control04.ctl Changes can also be checked with:<\/p>\n [crayon] 2. Using the Pfile (Parameter file) to make copies<\/strong> The following code creates a pfile.<\/span> “initSID_NAME.ora” in “\/u01\/app\/oracle\/product\/10.2.0\/db_1\/dbs\/”. In this example we have named the pfile initSMP.ora. Using Vi or WinSCP’s text editor we can create the following configuration according our requirements: Create an spfile from the pfile after finishing working on the pfile. startup The database can be opened and checked using the following syntax. NAME<\/p>\n ——————————————————————————–<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control01.ctl<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control02.ctl<\/p>\n \/u01\/app\/oracle\/oradata\/smp\/control03.ctl<\/p>\n \/u02\/IndexData\/smp\/control04.ctl<\/p>\n \/u03\/smp\/control05.ctl If the dbms is unable to open a control file then it cannot open the database. Suggested solutions to this type of issue:<\/p>\n \u2022 Delete the problematic control file, replace it with another functioning one and rename it.<\/p>\n \u2022 If the other control files are in working order, delete the control file from the spfile (by using the same method as creating a pfile).<\/p>\n <\/p>\n Accessing Controlfile information<\/p>\n V$CONTROLFILE : Contains the names and statuses of controlfiles.<\/p>\n V$PARAMETER : Statuses and locations\/paths.<\/p>\n V$CONTROLFILE_RECORD_SECTION : Datafiles and the objects that they contain (such as record_size, records_total)<\/p>\n <\/p>\n The performance view information listed below can be accessed through a control file:<\/p>\n \u2022 V$BACKUP<\/p>\n \u2022 V$DATAFILE<\/p>\n \u2022 V$TEMPFILE<\/p>\n \u2022 V$TABLESPACE<\/p>\n \u2022 V$ARCHIVE<\/p>\n \u2022 V$LOG<\/p>\n \u2022 V$LOGFILE<\/p>\n \u2022 V$LOGHIST<\/p>\n \u2022 V$ARCHIVED_LOG<\/p>\n \u2022 V$DATABASE<\/p>\n","protected":false},"excerpt":{"rendered":" The Control File can be considered to be the most important file in a database, it is the identity of the database.<\/p>\n","protected":false},"author":1,"featured_media":3420,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[383,338],"tags":[345],"class_list":["post-2605","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dba_i","category-oracle-tr","tag-oracle"],"_links":{"self":[{"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/posts\/2605","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/comments?post=2605"}],"version-history":[{"count":1,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/posts\/2605\/revisions"}],"predecessor-version":[{"id":4823,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/posts\/2605\/revisions\/4823"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sysdba.org\/en\/wp-json\/"}],"wp:attachment":[{"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/media?parent=2605"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/categories?post=2605"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sysdba.org\/en\/wp-json\/wp\/v2\/tags?post=2605"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n[crayon]
\nALTER SYSTEM SET control_files = ‘\/u01\/app\/oracle\/oradata\/smp\/control01.ctl’,<\/p>\n
\n[\/crayon]<\/p>\n
\nshutdown immediate
\n[\/crayon]<\/p>\n
\n[oracle@rhel ~]$ cp \/u01\/app\/oracle\/oradata\/smp\/control01.ctl \/u02\/IndexData\/smp\/control04.ct
\n[\/crayon]<\/p>\n
\nstartup
\n[\/crayon]<\/p>\n
\nselect name from v$controlfile;<\/p>\n
\n[\/crayon]<\/p>\n
\nSQL> show parameter control_files ;
\n[\/crayon]<\/p>\n
\n[crayon]
\nshutdown immediate
\n[\/crayon]<\/p>\n
\n[crayon]
\ncreate pfile from spfile;
\n[\/crayon]<\/p>\n
\n[crayon]
\n[oracle@rhel ~]$ cp \/u01\/app\/oracle\/oradata\/smp\/control01.ctl \/u03\/smp\/control05.ctl
\n[\/crayon]<\/p>\n
\n[crayon]
\n*.control_files=’\/u01\/app\/oracle\/oradata\/smp\/control01.ctl’,’\/u01\/app\/oracle\/oradata\/smp\/control02.ctl’,’\/u01\/app\/oracle\/oradata\/smp\/control03.ctl’,’\/u02\/IndexData\/smp\/control04.ctl’,’\/u03\/smp\/control05.ctl’
\n[\/crayon]<\/p>\n
\n[crayon]
\ncreate spfile from pfile;<\/p>\n
\n[\/crayon]<\/p>\n
\n[crayon]
\nselect name from v$controlfile;<\/p>\n
\n[\/crayon]<\/p>\n