Error :

RMAN> BACKUP AS COMPRESSED BACKUPSET DATABASE PLUS ARCHIVELOG;
Starting backup at 18-NOV-21
current log archived
using channel ORA_DISK_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 11/18/2021 17:29:50
RMAN-06059: expected archived log not found, loss of archived log compromises recoverability
ORA-19625: error identifying file /u02/immam/db/apps_st/data/archive/1_500_1195296918.dbf
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3

Solution :

Once in a while, there will be an archive log that is expired but not deleted.
If that is the case, there is an easy answer :

RMAN> crosscheck archivelog all;
RMAN> list expired archivelog all;
RMAN> delete expired archivelog all;

Now, run the backup again.. It will work !!

1} V$CONTROLFILE

Lists the names and status of the control files.

2} V$DATABASE

Contains database information from the control files.

3} V$DATAFILE

Contains data file information from control file.

4} V$INSTANCE

Displays the state of the current instance.

5} V$PARAMETER

Lists parameters and values currently in effect for the Session also status and location of all parameters.

 
6} V$SESSION

Lists session information for each current session.

 
7} V$SGA

Contains summary information on SGA.

 
8} V$SPPARAMETER

Lists the contents of SPFILE.

 
9} V$TABLESPACE

Displays tablespace information from the control file.

 
10} V$THREAD

Contains thread information from control file.

 
11} V$VERSION

Version numbers of core library components in oracle server.

12} V$FIXED_TABLE

To find list of data dictionary views.

 
13} V$CONTROLFILE_RECORD_SECTION

Provides information about the Control file record section.

14}SHOW PARAMETER CONTROL_FILES

Lists the name, status and location of Control files.

15}V$THREAD

To display the current redo log group, the no. of online redo log groups and current sequence number.

16} V$LOGFILE

Displays each redo log group, member and status of each Member.

17} V$LOG 

Same as above.

18} V$DATABASE_PROPERTIES

Name of default tablespaces.

19}V$DBA_TABLESPACES

Complete information about tablespaces.

20}V$DBA_DATA_FILES

Complete information of the files present in the Tablespaces.

21} V$DBA_TEMP_FILES

File’s information of temporary tablespace.

22} V$DBA_EXTENTS

To check the extents for a given segment.

23} V$DBA_SEGMENTS

View to get number of extents and blocks allocated to a Segment.

24} V$DBA_FREE_SPACE

Displays free extents in tablespace.

25} V$DBA_ROLLBACK_SEGS

To obtain information about all the undo segments In the database. {IMP*:-Information about undo segments that are offline can be seen only in this view.}

26}V$ROLLSTAT & V$ROLLNAME

Views to obtain the statistics of the undo Segments currently used by the instance.

27} V$TRANSACTION & V$SESSION

To check the use of a undo segment by Currently active transactions.

28} V$DBA_TABLES

All the information about tables can be obtained here.

29} V$DBA_OBJECTS

All the information about objects in table can be obtained here.

30} V$DBA_UNUSED_COL_TABS

To identify tables with unused columns.

31} V$DBA_PARTIAL_DROP_TABS

To identify tables that have partially Completed DROP columns operations.

32}V$DBA_INDEXES

Provides information on the indexes.

33}V$DBA_IND_COLUMNS

Provides information on the columns indexed.

34}V$OBJECT _USAGE

Provides information on the usage of an index.

35}V$DBA_CONSTRAINTS

To obtain name, type and status of all constraints.

36}V$DBA_CONS_COLUMNS

To obtain the columns in the constraints on table.

37}V$DBA_USERS

To obtain information about account status, default Tablespace for users.

38}V$DBA_PROPERTIES  

View to display passwd profile information.

39}V$DBA_TS_QUOTAS 

Amount of space a user can use in tablespaces.

40}V$DBA_SYS_PRIVS   

Lists system privileges granted to users and roles.

41} V$SESSION_PRIVS   

Lists the privileges that are currently available to user.

42} V$DBA_TAB_PRIVS

Lists all grants on all objects in the database.

43}V$DBA_COL_PRIVS 

Describes all object grants in the database.

44}V$DBA_ROLES

All roles that exist in the database.

45}V$DBA_ROLES_PRIVS

Roles granted to users and roles.

46}V$ROLE_ROL_PRIVS

Roles that are granted to roles.

47}V$DBA_SYS_PRIVS  

System privileges granted to users and roles.

48}V$ROLE_SYS_PRIVS

System privileges granted to roles.

49}V$ROLE_TAB_PRIVS

Object privileges granted to roles.

50}V$SESSION_ROLES

Roles that the user currently has enabled