.
\nThe file name convert parameters are not dynamic and require a restart of the instance. An enhancement request was filled in 2011. I mentioned recently on Twitter that it can be annoying with Active Data Guard when a file on the primary server is created on a path that has no file name conversion. However, Ian Baugaard mentioned that there is a workaround for this specific case because db_create_file_dest is dynamic:
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\n\n\nI recall seeing a MOS note indicating the order of precedence when it comes to db_file_name_convert and db_create_file_dest. The latter wins and makes config much easier especially when using OMF and ASM
\n— Ian Baugaard (@IanBaugaard) July 5, 2018
I’ve quickly created a 18c Data Guard configuration on the Oracle Cloud DBaaS to test it and here it is.
\nIn the primary database and the standby database, here are the datafiles:
\n\nRMAN> report schema;\n \nReport of database schema for database with db_unique_name ORCL_01\n \nList of Permanent Datafiles\n===========================\nFile Size(MB) Tablespace RB segs Datafile Name\n---- -------- -------------------- ------- ------------------------\n1 830 SYSTEM YES /u02/app/oracle/oradata/ORCL/system01.dbf\n3 510 SYSAUX NO /u02/app/oracle/oradata/ORCL/sysaux01.dbf\n4 60 UNDOTBS1 YES /u02/app/oracle/oradata/ORCL/undotbs01.dbf\n5 340 PDB$SEED:SYSTEM NO /u02/app/oracle/oradata/ORCL/pdbseed/system01.dbf\n6 620 PDB$SEED:SYSAUX NO /u02/app/oracle/oradata/ORCL/pdbseed/sysaux01.dbf\n7 5 USERS NO /u02/app/oracle/oradata/ORCL/users01.dbf\n8 200 PDB$SEED:UNDOTBS1 NO /u02/app/oracle/oradata/ORCL/pdbseed/undotbs01.dbf\n12 340 PDB1:SYSTEM YES /u02/app/oracle/oradata/ORCL/PDB1/system01.dbf\n13 620 PDB1:SYSAUX NO /u02/app/oracle/oradata/ORCL/PDB1/sysaux01.dbf\n14 200 PDB1:UNDOTBS1 YES /u02/app/oracle/oradata/ORCL/PDB1/undotbs01.dbf\n15 50 PDB1:USERS NO /u02/app/oracle/oradata/ORCL/PDB1/PDB1_users01.dbf\n \nList of Temporary Files\n=======================\nFile Size(MB) Tablespace Maxsize(MB) Tempfile Name\n---- -------- -------------------- ----------- --------------------\n1 33 TEMP 32767 /u04/app/oracle/oradata/temp/temp01.dbf\n2 62 PDB$SEED:TEMP 32767 /u04/app/oracle/oradata/temp/pdbseed_temp012018-02-08_13-49-27-256-PM.dbf\n4 62 PDB1:TEMP 32767 /u04/app/oracle/oradata/temp/temp012018-02-08_13-49-27-256-PM.dbf\nThe properties of the standby database define no DbFileNameConvert because the directory structure is supposed to be the same:
\n\nDGMGRL> show configuration\n \nConfiguration - fsc\n \n Protection Mode: MaxPerformance\n Members:\n ORCL_01 - Primary database\n ORCL_02 - Physical standby database\n \nFast-Start Failover: DISABLED\n \nConfiguration Status:\nSUCCESS (status updated 45 seconds ago)\n \n \nDGMGRL> show database verbose 'ORCL_02';\n \nDatabase - ORCL_02\n \n Role: PHYSICAL STANDBY\n Intended State: APPLY-ON\n Transport Lag: 0 seconds (computed 0 seconds ago)\n Apply Lag: 0 seconds (computed 0 seconds ago)\n Average Apply Rate: 15.00 KByte/s\n Active Apply Rate: 532.00 KByte/s\n Maximum Apply Rate: 535.00 KByte/s\n Real Time Query: ON\n Instance(s):\n ORCL\n \n Properties:\n DGConnectIdentifier = 'ORCL_02'\n...\n DbFileNameConvert = ''\n LogFileNameConvert = 'dummy, dummy'\n...\n \n Log file locations:\n Alert log : /u01/app/oracle/diag/rdbms/orcl_02/ORCL/trace/alert_ORCL.log\n Data Guard Broker log : /u01/app/oracle/diag/rdbms/orcl_02/ORCL/trace/drcORCL.log\n \nDatabase Status:\nSUCCESS\nYou can see that Oracle defines a dummy log file name convert. This a good idea to avoid some RMAN duplicate issues.
\nOn the standby server, I have no db_create_file_dest defined:
\n\nSQL> show parameter create%dest\n \nNAME TYPE VALUE\n------------------------------------ ----------- ------------------------------\ndb_create_file_dest string\ndb_create_online_log_dest_1 string .\ndb_create_online_log_dest_2 string\ndb_create_online_log_dest_3 string\ndb_create_online_log_dest_4 string\ndb_create_online_log_dest_5 string\nNote that the Oracle Cloud DBaaS defines it. I’ve reset it for the purpose of this demo.
\nI create a new filesystem on the primary server:
\n\n[root@DG-dg01 opc]# mkdir /DATA ; chown oracle:dba /DATA\nI create a datafile on this new filesystem:
\n\nSQL> alter session set container=PDB1;\nSession altered.\n \nSQL> create tablespace FRANCK datafile '/DATA/franck.dbf' size 100M;\nTablespace created.\nThe apply is stuck:
\n\nDGMGRL> show database 'ORCL_02';\n \nDatabase - ORCL_02\n \n Role: PHYSICAL STANDBY\n Intended State: APPLY-ON\n Transport Lag: 0 seconds (computed 2 seconds ago)\n Apply Lag: 11 seconds (computed 2 seconds ago)\n Average Apply Rate: 16.00 KByte/s\n Real Time Query: OFF\n Instance(s):\n ORCL\n \n Database Error(s):\n ORA-16766: Redo Apply is stopped\n \nDatabase Status:\nERROR\nThe standby alert.log shows the error about the impossibility to create the datafile:
\n\n2018-07-06T08:04:59.077730+00:00\nErrors in file /u01/app/oracle/diag/rdbms/orcl_02/ORCL/trace/ORCL_pr00_29393.trc:\nORA-01274: cannot add data file that was originally created as '/DATA/franck.dbf'\n2018-07-06T08:04:59.111881+00:00\nBackground Media Recovery process shutdown (ORCL)\nThe first idea is to set a db_file_name_convert, however, this requires an instance restart, which means downtime when you have sessions on the Active Data Guard standby:
\n\nDGMGRL> edit database 'ORCL_02' set property DbFileNameConvert='/DATA,/u02/app/oracle/oradata/ORCL';\nWarning: ORA-16675: database instance restart required for property value modification to take effect\n \nProperty \"dbfilenameconvert\" updated\n \nDGMGRL> show database 'ORCL_02';\n \nDatabase - ORCL_02\n \n Role: PHYSICAL STANDBY\n Intended State: APPLY-ON\n Transport Lag: 0 seconds (computed 2 seconds ago)\n Apply Lag: 3 minutes 32 seconds (computed 2 seconds ago)\n Average Apply Rate: 16.00 KByte/s\n Real Time Query: OFF\n Instance(s):\n ORCL\n Warning: ORA-16675: database instance restart required for property value modification to\n take effect\n Warning: ORA-16714: the value of property DbFileNameConvert is inconsistent with the member setting\n \n Database Error(s):\n ORA-16766: Redo Apply is stopped\n \n Database Warning(s):\n ORA-16853: apply lag has exceeded specified threshold\n \nDatabase Status:\nERROR\nThe solution is set db_create_file_dest which, on the standby, has higher priority than the convert:
\n\nSQL> alter system set db_create_file_dest='/u02/app/oracle/oradata';\nSystem altered.\nI restart the apply:
\n\nDGMGRL> edit database 'ORCL_02' set state=apply-on;\nSucceeded.\nNo need to restart and future datafile creations will be created there. However, it is too late for this datafile as it has already been created as UNNAMED in the controlfile:
\n\nORA-01186: file 18 failed verification tests\nORA-01157: cannot identify/lock data file 18 - see DBWR trace file\nORA-01111: name for data file 18 is unknown - rename to correct file\nORA-01110: data file 18: '/u01/app/oracle/product/18.0.0/dbhome_1/dbs/UNNAMED00018'\nThen I must manually create it, but I cannot do that while I am in standby_file_management=auto:
\n\nSQL> alter session set container=PDB1;\nSession altered.\n \nSQL> alter database create datafile '/u01/app/oracle/product/18.0.0/dbhome_1/dbs/UNNAMED00018' as '/u02/app/oracle/oradata/ORCL/franck.dbf';\nalter database create datafile '/u01/app/oracle/product/18.0.0/dbhome_1/dbs/UNNAMED00018' as '/u02/app/oracle/oradata/ORCL/franck.dbf'\n*\nERROR at line 1:\nORA-01275: Operation CREATE DATAFILE is not allowed if standby file management\nis automatic.\nThis can be changed dynamically:
\n\nDGMGRL> edit database 'ORCL_02' set property StandbyFileManagement=manual;\nProperty \"standbyfilemanagement\" updated\nAnd then the creation is possible:
\n\nSQL> alter session set container=PDB1;\nSession altered.\n \nSQL> alter database create datafile '/u01/app/oracle/product/18.0.0/dbhome_1/dbs/UNNAMED00018' as new;\nDatabase altered.\nYou can see that because I have defined db_create_file_dest, I don’t need to name the datafile and create it as OMF with the ‘new’ keyword.
\nNow I can start the apply and it will resolve the gap:
\n\nDGMGRL> edit database 'ORCL_02' set state=apply-on;\nSucceeded.\n \nDGMGRL> show database 'ORCL_02';\n \nDatabase - ORCL_02\n \n Role: PHYSICAL STANDBY\n Intended State: APPLY-ON\n Transport Lag: 0 seconds (computed 3 seconds ago)\n Apply Lag: 0 seconds (computed 3 seconds ago)\n Average Apply Rate: 22.00 KByte/s\n Real Time Query: ON\n Instance(s):\n ORCL\n Warning: ORA-16675: database instance restart required for property value modification to take effect\n Warning: ORA-16714: the value of property DbFileNameConvert is inconsistent with the member setting\n \nDatabase Status:\nWARNING\nDo not forget to put back standby_file_management”to auto:
\n\nDGMGRL> edit database 'ORCL_02' set property StandbyFileManagement=auto;\nProperty \"standbyfilemanagement\" updated\nSo, now that db_create_file_dest is set, new datafiles will be created automatically as OMF (Oracle Managed Files), without caring about file name conversion:
\n\nSQL> alter session set container=PDB1;\nSession altered.\n \nSQL> alter tablespace FRANCK add datafile '/DATA/franck2.dbf' size 100M;\nTablespace altered.\nThis is confirmed from the standby alert.log:
\n\n(4):Datafile 19 added to flashback set\n(4):Successfully added datafile 19 to media recovery\n(4):Datafile #19: '/u02/app/oracle/oradata/ORCL_02/7050211FE75F26FAE05392781D0AADAA/datafile/o1_mf_franck_fmybw332_.dbf'\nAlways define db_create_file_dest in the standby database so that datafiles will be created. Better to have them at the wrong place rather than stopping the apply. And anyway, if you don’t like the OMF names, and you are at least in 12c Enterprise Edition, you can change their name later with online move:
\n\nSQL> alter session set container=PDB1;\nSession altered.\n \nSQL> alter database move datafile '/u02/app/oracle/oradata/ORCL_02/7050211FE75F26FAE05392781D0AADAA/datafile/o1_mf_franck_fmybw332_.dbf' to '/u02/app/oracle/oradata/ORCL/franck2.dbf';\nDatabase altered.\n