The stubborn standby redo log

I publish this question here, Due to the similarity between the technologies, and I know for you this is very familiar.
I have a dowstreams which has four standbys redo log groups. One of these groups is still in a redo of the day 23/04/2010. This old redo is not filed, always there.
this implies that the database downstreams only work with three groups of redo log and some oacaciones all these are in active status and at that time the view v $ archived_dest returns error for that destination (downstreams).
The question is:
how I can eliminate that standby redo log which is not being archived.
Thank you very much for your attention

I run this query
SELECT GROUP#, THREAD#, SEQUENCE#, ARCHIVED, STATUS,FIRST_TIME FROM V$STANDBY_LOG;
and it returns me
GROUP#____THREAD#__SEQUENCE#__ARC__STATUS__________FIRST_TIME
4___________ 1__________0_________NO____UNASSIGNED
5 ___________1_________2760_______YES_____ACTIVE__________04/05/10
6____________1________2328 _______YES______ACTIVE__________27/04/10 --> The stubborn redo
7____________1__________0_________NO_____UNASSIGNED

Similar Messages

  • The file structure online redo log, archived redo log and standby redo log

    I have read some Oracle documentation for file structure and settings in Data Guard environment. But I still have some doubts. What is the best file structure or settings in Oracle 10.2.0.4 on UNIX for a data guard environment with 4 primary databases and 4 physical standby databases. Based on Oracle documents, there are 3 redo logs. They are: online redo logs, archived redo logs and standby redo logs. The basic settings are:
    1. Online redo logs --- This redo log must be on Primary database and logical standby database. But it is not necessary to be on physical standby database because physical standby is not open. It doesn't generate redo log. However, if don't set up online redo log on physical standby, when primary failover and switch standby as primary. How can standby perform without online redo logs? In my standby databases, online redo logs have been set up.
    2. Archived redo logs --- It is obviously that primary database, logical and physical standby database all need to have this log file being set up. Primary use it to archive log files and ship to standby. Standby use it to receive data from archived log and apply to database.
    3. Standby redo logs --- In the document, it says A standby redo log is similar to an online redo log, except that a standby redo log is used to store redo data received from another database. A standby redo log is required if you want to implement: The maximum protection and maximum availability levels of data protection and Real-time apply as well as Cascaded destinations. So it seems that this standby redo log only should be set up on standby database, not on primary database. Am my understanding correct? Because I review current redo log settings on my environment, I have found that Standby redo log directory and files have been set up on both primary and standby databases. I would like to get more information and education from experts. What is the best setting or structure on primary and standby database?

    FZheng:
    Thanks for your input. It is clear that we need 3 type of redo logs on both databases. You answer my question.
    But I have another one. In oracle ducument, it says If you have configured a standby redo log on one or more standby databases in the configuration, ensure the size of the current standby redo log file on each standby database exactly matches the size of the current online redo log file on the primary database. It says: At log switch time, if there are no available standby redo log files that match the size of the new current online redo log file on the primary database. The primary database will shut down
    My current one data gurard envirnment setting is: On primary DB, online redo log group size is 512M and standby redo log group size is 500M. On the standby DB, online redo log group size is 500M and standby redo log group size is 750M.
    This was setup by someone I don't know. Is this setting OK? or I should change Standby Redo Log on standby DB to 512M to exactly meatch with redo log size on primary?
    Edited by: 853153 on Jun 22, 2011 9:42 AM

  • Standby Redo Log Files and Directory Structure in Standby Site

    Hi Guru's
    I just want to confirm, i know that if the Directory structure is different i need to mention these 2 parameter in pfile
    on primary site:
    DB_CONVERT_DATAFILE='standby','primary'
    LOG_CONVERT_DATAFILE='standby','primary'
    On secondary Site:
    DB_CONVERT_DATAFILE='primary','standby'
    LOG_CONVERT_DATAFILE='primary','standby'
    But i want to confirm this wheather i need to issue the complete path of the directory in both the above paramtere:
    like:
    DB_CONVERT_DATAFILE='/u01/oracle/app/oracle/oradata/standby','/u01/oracle/app/oracle/oradata/primary'
    LOG_CONVERT_DATAFILE='/u01/oracle/app/oracle/oradata/standby','/u01/oracle/app/oracle/oradata/primary'
    Second Confusion:-
    After transferring Redo Standby log files created on primary and taken to standby on the above mentioned directory structure and after restoring the backup of primary db alongwith the standby control file will not impact the physical standby redo log placed on the above mentioned location.
    Thanks in advance for your help

    Hello,
    Regarding your 1st question, you need to provide the complete path and not just the directory name.
    On the standby:
    db_file_name_convert='<Full path of the datafiles on primary server>','<full path of the datafiles to be stored on the standby server>';
    log_file_name_convert='<Full path of the redo logfiles on primary server>','<full path of the redo logfiles on the standby server>';
    Second Confusion:-
    After transferring Redo Standby log files created on primary and taken to standby on the above mentioned directory structure and after restoring the backup of primary db alongwith the standby control file will not impact the physical standby redo log placed on the above mentioned location.
    How are you creating the standby database ? Using RMAN duplicate or through the restore/recovery options ?
    You can create the standby redo logs later.
    Regards,
    Shivananda

  • Why do we need standby redo log on Primary database.

    Hi Gurus,
    I was going through the document in OBE,
    http://www.oracle.com/technology/obe/11gr1_db/ha/dataguard/physstby/physstdby.htm
    I have two queries:
    1) I noticed the statement -
    "Configure the primary database to receive redo data, by adding the standby logfiles to the primary. "
    Why do we have to create standby redo log on a primary database?
    2) There is another statement --
    "It is highly recommended that you have one more standby redo log group than you have online redo log groups as the primary database. The files must be the same size or larger than the primary database’s online redo logs. "
    Why do we need one additional standby redo log group than in Primary database.
    Could anyone please explain to me in simple words.
    Thanks
    Cherrish Vaidiyan

    Hi,
    1. Standby redo logs are used only when the database_role is standby, it is recommended to be added in primary also so that they can be used on role reversal, however during normal working standby redo logs will not be used at all on primary.
    2. In case of 3 online redo log groups, it is recommended to use 4 standby redo log group this is in case if log switching is happening frequently on primary and all 3 standby redo logs are still not completely archived on the standby and 4th can be used here as there will be some delay on standby due to network or slowness of arch on standby.
    Use of the standby redo log groups depends on the redo generation rate, you can see only 2 standby redo logs are getting used while you have 4 standby redo log groups, when the redo generation rate is less.
    So it is recommended to have one more standby redo log group when redo generation rate is high and all of the existing standby redo log group are getting used.
    Regards
    Anudeep

  • Use of standby redo log files in primary database

    Hi All,
    What is the exact use of setting up standby redo log files in the primary database on a data guard setup?
    any good documents?

    A standby redo log is required for the maximum protection and maximum availability modes and the LGWR ASYNC transport mode is recommended for all databases. Data Guard can recover and apply more redo data from a standby redo log than from archived redo log files alone.
    You should plan the standby redo log configuration and create all required log groups and group members when you create the standby database. For increased availability, consider multiplexing the standby redo log files, similar to the way that online redo log files are multiplexed.
    refer the link,and Perform the following steps to configure the standby redo log.:-
    http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703
    If the real-time apply feature is enabled, log apply services can apply redo data as it is received, without waiting for the current standby redo log file to be archived. This results in faster switchover and failover times because the standby redo log files have been applied already to the standby database by the time the failover or switchover begins.
    refer the link
    http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/log_apply.htm#i1023371

  • Online redo logs vs standby redo logs

    Hi All,
    Oracle version : 10.2.0.4
    OS : SunOS 5.10 Generic_118855-36 i86pc i386 i86pc
    This might be a silly question for the experts :(
    We are having 2 standby databases and 1 logical database. Everything is running fine , I have one confusion : My primary server having 3 online redo log files and 3 standby redo log files (on primary local), but as per the architecture standby redo logs should be on standby server.My question is whether standby redo logs on standby are online redo logs of standby server or standby redo logs of primary server. e.g If i perform a log switch on primary then what is the role of sync and affirm, will lgwr write parallel on online redo logs ,standby redo logs (of primary) or online redo logs (of primary) and online redo logs (which is known as standby redo logs on standby ). Please help me to understand the scenerio.
    Thanks in advance!

    RFS receives redo information from the primary database.
    RFS can write the redo into standby redo logs or directly to archived redo logs. Each LNSn and ARCn process from the primary database has its own RFS process.
    A standby redo log is used only when the database is in the standby role to store redo data received from the primary database. Standby redo logs form a separate pool of log file groups.
    Configuring standby redo log files is highly recommended on all standby databases in a Data Guard configuration, including the primary database to aid in role reversal.
    A standby redo log is required to implement:
    • The maximum protection and maximum availability levels of data protection
    • Real-time apply
    • Cascaded redo log destinations
    Standby redo logs are recommended for maximum performance data protection mode. Unless you are using the real-time apply feature, standby redo logs must be archived before the data can be applied to the standby database. The standby archival operation occurs automatically.

  • What is the purpose of standby redo log files

    Hi,
    What is the purpose of the standby redo log files in DR?
    what if the standby redo log files are created? or else not created?
    Please explain
    Thanks

    3.1.3 Configure a Standby Redo LogA standby redo log is required for the maximum protection and maximum availability modes and the LGWR ASYNC transport mode is recommended for all databases. Data Guard can recover and apply more redo data from a standby redo log than from archived redo log files alone.
    You should plan the standby redo log configuration and create all required log groups and group members when you create the standby database. For increased availability, consider multiplexing the standby redo log files, similar to the way that online redo log files are multiplexed.>
    Reference http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703
    HTH
    Anand

  • Where RFS exactly write redo data ?  ( archived redo log or standby redo log ) ?

    Good Morning to all ;
    I am getting bit confused from oracle official link . REF_LINK : Log Apply Services
    Redo data transmitted from the primary database is received by the RFS on the standby system ,
    where the RFS process writes the redo data to either archived redo log files  or  standby redo log files.
    In standby site , does rfs write redo data in any one file or both ?
    Thanks in advance ..

    Hi GTS,
    GTS (DBA) wrote:
    Primary & standby log file size should be same - this is okay.
    1) what are trying to disclose about  largest & smallest here ? -  You are confusing.
    Read: http://docs.oracle.com/cd/E11882_01/server.112/e25608/log_transport.htm#SBYDB4752
    "Each standby redo log file must be at least as large as the largest redo log file in the redo log of the redo source database. For administrative ease, Oracle recommends that all redo log files in the redo log at the redo source database and the standby redo log at a redo transport destination be of the same size."
    GTS (DBA) wrote:
    2) what abt group members ? should be same as primary or need  to add some members additionally. ?
    Data Guard best practice for performance, is to create one member per each group in standby DB. on standby DB, one member per group is reasonable enough. why? to avoid write penalty; writing to more than one log files at the standby DB.
    SCENARIO 1: if in your source primary DB you have 2 log member per group, in standby DB you can have 1 member  per group, additionally create an extra group.
    primary
    standby
    Member per group
    2
    1
    Number of log group
    4
    5
    SCENARIO 2: you can also have this scenario 2 but i will not encourage it
    primary
    standby
    Member per group
    2
    2
    Number of log group
    4
    5
    GTS (DBA) wrote:
    All standby redo logs of the correct size have not yet been archived.
      - at this situation , can we force on standby site ? any possibilities ? 
    you can not force it , just size your standby redo files correctly and make sure you don not have network failure that will cause redo gap.
    hope there is clarity now
    Tobi

  • Physical standby database standby redo log problem

    Hello
    We have a physical standby database , I've created some standby redo log files but my problem is that they aren't used,
    their status in v$stanby_log view is UNASSIGNED
    and I see this message (ORA-16086: standby database does not contain available standby log files) in primary database alert_log file
    while when I run "alter system switch logfile" in the primary database it transfer redo logs to the physsical standby database
    and archive log file will be created in standby database
    I've even recreated the standby redo log files and I added new ones to them but the problem wasn't solved
    Do you know what is problem ?
    elect group#,THREAD#,BYTES,STATUS from V$STANDBY_LOG;
    group#     THREAD#      BYTES       STATUS
    1                   0                   524288000                   UNASSIGNED                  
    2                   0                   524288000                   UNASSIGNED                  
    3                   0                   524288000                   UNASSIGNED                  
    8                   0                   524288000                   UNASSIGNED                  
    9                   0                   524288000                   UNASSIGNED                  
    10                   0                   524288000                   UNASSIGNED                  
    select group#,THREAD#,BYTES,MEMBERS,STATUS from v$log;
    group#                    THREAD#                    BYTES                    MEMBERS                    STATUS
    4                   1                   524288000                   2                   CLEARING                  
    7                   1                   524288000                   2                   CLEARING_CURRENT                  
    6                   1                   524288000                   2                   CLEARING                  
    5                   1                   524288000                   2                   CLEARING                  
    thanks

    Hello Anurag
    Thank you for your reply
    I have found some issue in the standby database alert_log too , in the standby database alert_log it has been written:
    RFS[782]: Assigned to RFS process 3919
    RFS[782]: Identified database type as 'physical standby'
    Primary database is in MAXIMUM AVAILABILITY mode
    Standby controlfile consistent with primary
    Primary database is in MAXIMUM AVAILABILITY mode
    Standby controlfile consistent with primary
    RFS[782]: No standby redo logfiles selected (reason:6)
    Sun Jan 31 13:59:43 2010
    Errors in file /u01/app/oracle/admin/tehrep/udump/tehrep_rfs_3919.trc:
    ORA-16086: standby database does not contain available standby log files
    Sun Jan 31 13:59:48 2010
    RFS[781]: Archived Log: '/disks/sda/tehrep/archivelogs/1_6516_670414641.dbf'
    Sun Jan 31 13:59:50 2010
    and the context "/u01/app/oracle/admin/tehrep/udump/tehrep_rfs_3919.trc"  is below :
    +/u01/app/oracle/admin/tehrep/udump/tehrep_rfs_3919.trc+
    Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
    With the Partitioning, OLAP and Data Mining options
    ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1
    System name:    Linux
    Node name:      linserver2.com
    Release:        2.6.9-42.ELsmp
    Version:        #1 SMP Wed Jul 12 23:27:17 EDT 2006
    Machine:        i686
    Instance name: tehrep
    Redo thread mounted by this instance: 1
    Oracle process number: 58
    Unix process pid: 3919, image: [email protected]
    *** SERVICE NAME:() 2010-01-31 13:59:43.865
    *** SESSION ID:(109.1225) 2010-01-31 13:59:43.865
    KCRRFLAS
    KCRRSNPS
    No space in recovery area for active standby redo logs
    The primary database is operating in MAXIMUM PROTECTION
    or MAXIMUM AVAILABILITY mode, and the standby database
    does not contain adequate disk space in the recovery area
    to safely archive the contents of the standby redo logfiles.
    ORA-16086: standby database does not contain available standby log files
    when I saw this line "No space in recovery area for active standby redo logs" I thought that STANDBY_ARCHIVE_DEST parameter points where that there is no enough space , but when I consider I found out that points a directory on disk a "sda" that has enough space , I don't know what that means
    by the way, at below I've written a section of the primary database alert_log context and "lgwr" trace file around Sun Jan 31 13:30:34 2010
    alert_log :
    ORA-16086: standby database does not contain available standby log files
    Sun Jan 31 13:30:34 2010
    LGWR: Failed to archive log 7 thread 1 sequence 6512 (16086)
    Thread 1 advanced to log sequence 6512
    Current log# 7 seq# 6512 mem# 0: /disks/sdb/tehrep/redo71.log
    Current log# 7 seq# 6512 mem# 1: /disks/sdd/tehrep/redo72.log
    LNSc started with pid=53, OS id=11451
    Sun Jan 31 13:36:34 2010
    Errors in file /u01/app/oracle/admin/tehrep/bdump/tehrep_lgwr_3692.trc:
    ORA-16086: standby database does not contain available standby log files
    Sun Jan 31 13:36:34 2010
    LGWR: Failed to archive log 5 thread 1 sequence 6513 (16086)
    Thread 1 advanced to log sequence 6513
    Current log# 5 seq# 6513 mem# 0: /disks/sdb/tehrep/redo51.log
    Current log# 5 seq# 6513 mem# 1: /disks/sdd/tehrep/redo52.log
    */u01/app/oracle/admin/tehrep/bdump/tehrep_lgwr_3692.trc file :*
    Error 16086 creating standby archive log file at host '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=linserver2.com
    +)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=tehrep_XPT.com)(INSTANCE_NAME=tehrep)(SERVER=dedicated)))'+
    *** 2010-01-31 13:30:34.712 60679 kcrr.c
    LGWR: Attempting destination LOG_ARCHIVE_DEST_3 network reconnect (16086)
    *** 2010-01-31 13:30:34.712 60679 kcrr.c
    LGWR: Destination LOG_ARCHIVE_DEST_3 network reconnect abandoned
    ORA-16086: standby database does not contain available standby log files
    *** 2010-01-31 13:30:34.712 60679 kcrr.c
    LGWR: Error 16086 creating archivelog file '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=linserver2.com)(PORT=1521
    +)))(CONNECT_DATA=(SERVICE_NAME=tehrep_XPT.com)(INSTANCE_NAME=tehrep)(SERVER=dedicated)))'+
    *** 2010-01-31 13:30:34.712 58941 kcrr.c
    kcrrfail: dest:3 err:16086 force:0 blast:1
    Receiving message from LNSc
    *** 2010-01-31 13:30:34.718 55444 kcrr.c
    Making upidhs request to LNSc (ocis 0x0xb648db48). Begin time is <01/31/2010 13:30:30> and NET_TIMEOUT <180> seconds
    NetServer pid:11196
    *** 2010-01-31 13:30:38.718 55616 kcrr.c
    upidhs done status 0
    *** 2010-01-31 13:36:31.062
    LGWR: Archivelog for thread 1 sequence 6513 will NOT be compressed
    *** 2010-01-31 13:36:31.062 53681 kcrr.c
    +Initializing NetServer[LNSc] for dest=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=linserver2.com)(PORT=1521)))(CO+
    NNECT_DATA=(SERVICE_NAME=tehrep_XPT.com)(INSTANCE_NAME=tehrep)(SERVER=dedicated))) mode SYNC
    LNSc is not running anymore.
    New SYNC LNSc needs to be started
    Waiting for subscriber count on LGWR-LNSc channel to go to zero
    Subscriber count went to zero - time now is <01/31/2010 13:36:31>
    Starting LNSc ...
    Waiting for LNSc to initialize itself
    *** 2010-01-31 13:36:34.116 53972 kcrr.c
    +Netserver LNSc [pid 11451] for mode SYNC has been initialized+
    Performing a channel reset to ignore previous responses
    +Successfully started LNSc [pid 11451] for dest (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=linserver2.com)(PORT=1+
    +521)))(CONNECT_DATA=(SERVICE_NAME=tehrep_XPT.com)(INSTANCE_NAME=tehrep)(SERVER=dedicated))) mode SYNC ocis=0x0xb648db48+
    *** 2010-01-31 13:36:34.116 54475 kcrr.c
    +Making upiahm request to LNSc [pid 11451]: Begin Time is <01/31/2010 13:36:31>. NET_TIMEOUT = <180> seconds+
    Waiting for LNSc to respond to upiahm
    *** 2010-01-31 13:36:34.266 54639 kcrr.c
    upiahm connect done status is 0
    Receiving message from LNSc
    Receiving message from LNSc
    Destination LOG_ARCHIVE_DEST_3 is in STANDBY RESYNCHRONIZATION mode
    Receiving message from LNSc

  • Apply standby redo log to physical stby db.

    Hi all,
    Facing a problem in the following scenario.
    I have dataguard configuration operating in maximum availability mode with a local standby db (A - lgwr sync not using real time apply) and a remote standby db (B - lgwr async). I then simualted a crash of my primary database with batch jobs running. Since the stby db A is in lgwr sync option ,all the commited data in the current online redo log has been transmitted to stby A and is present in its stby redo log (Group 2).How do I apply this stby redo log to the remote stby db.
    Tried the following methods.
    1.ftp the stby redo log to the remote db and tried to regiter it, got an error that it is not completely archived.
    2.issued the recover standby database command and supplied the stby redo log when it asked for the sequence in the stby redo, got an error saying there is corruption in a block(tried this option multiple times ended up with the same result.)
    Regards.

    Hello,
    Did you try "alter database recover managed standby database finish" on the standby database ?
    Regards,
    Shivananda

  • Resizing online and standby redo log in dataguard setup.

    In 10gr2 dataguard i would like to increase redo logsize from 50M to 100M.
    on primary
    standby_file_management=manual
    added online redo groups with 100M
    log switched
    drop old one and readded with 100m
    deleted log added in step2.
    same for standby redo logs.
    On standby
    was able to resize standby redo logs.
    but cannot resize online redologs status is clearing or clearing_current.
    please comment. thanks.

    I assume you just had to wait until the Primary switched out of that online log so it became inactive at the standby as well? We track where the Primary is by marking the online redo log files at the standby as clearing_current so you can tell where the primary was at any given moment.
    Make sure you create new standby redo log files at the Primary and Standby to match the new online redo log file size.
    Larry

  • Standby Redo Log Groups

    I have a problem on my standby database.
    When I check the status of v$standby_log
    one loggroup by one is getting active.
    At the end all 15 loggroups have the status active and I get the message no logs of size #### available
    What is the reason that those logs are not written to disk ?
    MRP is running.
    database is in archivelogmode
    flashback is enabled
    Recover database using backup controlfile is not working
    archive log all not allowed the backup controlfile....

    This issue is normally found when the 'standby redo' log on the standby is not as large as the 'redo' log on the primary.
    Per oracle, all standby redo log size should be equal to or larger than the largest redo log on the primary database. Oracle recommends keeping all the redo logs and standby logs of the same size.
    Would you like to confirm all logs have been set as oracle mandates?
    Cheers.

  • Standby Redo log creation

    DB version: 11.2
    OS : AIX 6.1
    We have a 2 node RAC. We have one Disk group for all datafiles, tempfiles, redo logs,..etc.
    Currenly in our primary DB, Redo logs look like
    SQL> SELECT a.group#, b.thread#, a.member, b.bytes
    FROM v$logfile a, v$log b WHERE a.group# = b.group#
    order by a.group# , b.thread#  2    3  ;
             GROUP#         THREAD# MEMBER                                BYTES
                  1               1 +ORCL_DG/orcl/orcl_log01.dbf         104857600
                  2               1 +ORCL_DG/orcl/orcl_log02.dbf         104857600
                  3               1 +ORCL_DG/orcl/orcl_log03.dbf         104857600
                  4               2 +ORCL_DG/orcl/orcl_log04.dbf         104857600
                  5               2 +ORCL_DG/orcl/orcl_log05.dbf         104857600
                  6               2 +ORCL_DG/orcl/orcl_log06.dbf         104857600
    6 rows selected.
    1 member per group
    3 group per instanceWe need to create a physical standby DB for the above DB with Real Time apply. For standby Redo logs, I need one extra log file for each Instance.
    So, I am going to add
         group# 7 for thread 1
         and
         group# 8 for thread 2
    Finally , SRLs will look like
             GROUP#         THREAD# MEMBER                                BYTES
                  1               1 +ORCL_DG/orcl/orcl_log01.dbf         104857600
                  2               1 +ORCL_DG/orcl/orcl_log02.dbf         104857600
                  3               1 +ORCL_DG/orcl/orcl_log03.dbf         104857600
               7               1 +ORCL_DG/orcl/orcl_log07.dbf         104857600  ------->  Additional
                  4               2 +ORCL_DG/orcl/orcl_log04.dbf         104857600
                  5               2 +ORCL_DG/orcl/orcl_log05.dbf         104857600
                  6               2 +ORCL_DG/orcl/orcl_log06.dbf         104857600
               8               2 +ORCL_DG/orcl/orcl_log08.dbf         104857600  ------->  AdditionalAnything wrong with my proposed SRL creation ?

    JOE_humble wrote:
    DB version: 11.2
    OS : AIX 6.1
    We have a 2 node RAC. We have one Disk group for all datafiles, tempfiles, redo logs,..etc.
    Currenly in our primary DB, Redo logs look like
    SQL> SELECT a.group#, b.thread#, a.member, b.bytes
    FROM v$logfile a, v$log b WHERE a.group# = b.group#
    order by a.group# , b.thread#  2    3  ;
    GROUP#         THREAD# MEMBER                                BYTES
    1               1 +ORCL_DG/orcl/orcl_log01.dbf         104857600
    2               1 +ORCL_DG/orcl/orcl_log02.dbf         104857600
    3               1 +ORCL_DG/orcl/orcl_log03.dbf         104857600
    4               2 +ORCL_DG/orcl/orcl_log04.dbf         104857600
    5               2 +ORCL_DG/orcl/orcl_log05.dbf         104857600
    6               2 +ORCL_DG/orcl/orcl_log06.dbf         104857600
    6 rows selected.
    1 member per group
    3 group per instanceWe need to create a physical standby DB for the above DB with Real Time apply. For standby Redo logs, I need one extra log file for each Instance.
    So, I am going to add
         group# 7 for thread 1
         and
         group# 8 for thread 2
    Finally , SRLs will look like
    GROUP#         THREAD# MEMBER                                BYTES
    1               1 +ORCL_DG/orcl/orcl_log01.dbf         104857600
    2               1 +ORCL_DG/orcl/orcl_log02.dbf         104857600
    3               1 +ORCL_DG/orcl/orcl_log03.dbf         104857600
               7               1 +ORCL_DG/orcl/orcl_log07.dbf         104857600  ------->  Additional
    4               2 +ORCL_DG/orcl/orcl_log04.dbf         104857600
    5               2 +ORCL_DG/orcl/orcl_log05.dbf         104857600
    6               2 +ORCL_DG/orcl/orcl_log06.dbf         104857600
               8               2 +ORCL_DG/orcl/orcl_log08.dbf         104857600  ------->  AdditionalAnything wrong with my proposed SRL creation ?You have to create equal numbers & equal or greater size of standby redo log files than Online redo log files.
    Refer http://www.pythian.com/news/581/oracle-standby-redo-logs/ to configure standby redo log files.

  • Standby redo log

    In what situation, standby redo logs are mandatory.
    I have the below settings and my DATA GAURD setup (10.2.0.3) is working fine without Stdby redo logs.
    Just wondering when do i need standby redo logs.
    SQL> show parameter log_Archive_dest_2
    NAME TYPE VALUE
    log_archive_dest_2 string SERVICE=TO_STANDBY LGWR ASYNC
    AFFIRM DB_UNIQUE_NAME=stand
    SQL> select protection_mode from v$database;
    PROTECTION_MODE
    MAXIMUM PERFORMANCE

    888442 wrote:
    In what situation, standby redo logs are mandatory.
    I have the below settings and my DATA GAURD setup (10.2.0.3) is working fine without Stdby redo logs.
    Just wondering when do i need standby redo logs.
    SQL> show parameter log_Archive_dest_2
    NAME TYPE VALUE
    log_archive_dest_2 string SERVICE=TO_STANDBY LGWR ASYNC AFFIRM DB_UNIQUE_NAME=stand
    SQL> select protection_mode from v$database;
    PROTECTION_MODE
    MAXIMUM PERFORMANCEHi,
    Standby Redo Logs (SRL) require when you are using MAX AVAILABILITY and MAX PROTECTIN protection modes. So SRL using for Real Time Apply.
    In your case (Max Performance) if you want real time apply on standby you must add SRLs to standby database.
    Best practice we adding standby redo logs to primary and standby database same time, but when database role is standby then using SRLs.
    You can ask, why also to primary? Because we can switchover to standby, then priamry role will change to standby, then will use SRLs.
    Regards
    Mahir M. Quluzade

  • Standby redo log group for particular thread

    hi masters,
    actually i am performing an experiment to create physical standbyt database on the same machine as my primary database.
    i ma going according to 'data guard admin guide'. while section for ading standby redo log group,it says that you have to add standby redo log group to "thread"....
    what is this thread? and how can i foind to which thread i have to assign the next redo log group??
    how can i find current thread??
    what if i dont add "to thread' clause in my statement:-
    ALTER DATABASE ADD STANDBY LOGFILE THREAD 5
    2> ('/oracle/dbs/log1c.rdo','/oracle/dbs/log2c.rdo') SIZE 500M;
    thanks and regards
    VD

    Vikrant,
    First a question: Do you have a RAC instance? If so the paragraph even doesn't apply to you and I'm not sure why you are questioning it.
    Secondly
    "The THREAD clause is required only if you want to add one or more standby redo log
    file groups to a specific primary database thread. If you do not include the THREAD
    clause and the configuration uses Real Application Clusters (RAC), Data Guard will
    automatically assign standby redo log file groups to threads at runtime as they are
    needed by the various RAC instances."
    this means you dont have to specify thread for RAC,as it will allocate one according to current thread.
    Your conclusion is incorrect.
    Where do you read the word 'current'?
    Oracle will likely simply make sure each instance has sufficient standby redolog groups, the requirement is 1 standby redolog group per group + 1 extra.
    Sybrand Bakker
    Senior Oracle DBA

Maybe you are looking for