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.

Similar Messages

Online Redo logs instead of Standby Redo logs

RDBMS Version: 11.2.0.3/Platform : RHEL 6.3
To migrate a 3TB Database to a new DB server , we are going to use RMAN DUPLICATE.
Step1. Take full backup of DB + Standby Control file at primary site and transfer the Bkp files to Standby site
Step2. At standy site, we will run the RMAN duplicate target database for standby
After the above step, we don't want to create the standby redo logs because the newly restored DB in standby server is going to be the new Prod DB which application will be pointing to.
So, Can I skip the Standby Redo log creation part and create Online redo logs instead ?
As mentioned earlier, Our objective is not to create a proper Dataguard Standby DB setup. We just want to clone our DB to another server using RMAN Duplicate.

Tom wrote:
RDBMS Version: 11.2.0.3/Platform : RHEL 6.3
To migrate a 3TB Database to a new DB server , we are going to use RMAN DUPLICATE.
Step1. Take full backup of DB + Standby Control file at primary site and transfer the Bkp files to Standby site
Step2. At standy site, we will run the RMAN duplicate target database for standby
After the above step, we don't want to create the standby redo logs because the newly restored DB in standby server is going to be the new Prod DB which application will be pointing to.
So, Can I skip the Standby Redo log creation part and create Online redo logs instead ?
As mentioned earlier, Our objective is not to create a proper Dataguard Standby DB setup. We just want to clone our DB to another server using RMAN Duplicate.
Hi,
Take full backup of DB + Standby Control
We just want to clone our DB to another server using RMAN Duplicate
If you want only clone database of production, why you are take Standby controlfile?
If you don't want create standby database then, why you using DUPLICATE command with FOR STANDBY option.
You can use DUPLICATE command for clone database, without for standby option.
If you say no, we want create standby database and we will perform swithover,
then yes, you can use online redo logs for max performance mode.
and you can create standby redo logs on all database, but this redo logs will use by database when database role
is standby.
Regards
Mahir M. Quluzade

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

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

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

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

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

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

Standby redo log file

Hi,
From oracle document i know in the standby side the RFS process writes to Standby redo log file -> archive log and the MRP procees applys the archive logs to the standby database.
my question is ,if we dont create standby redo log file what happens?

Hello;
When redo is received by an RFS on the standby , the RFS process writes the redo data into archived redo logs or optionally to the SRL.
Standby Redo Logs is where the RFS process at your Standby database writes incoming redo, they help performance because the RFS does not have to create the Archive log file.
Standby redo logs are a component of the Data Guard setup. They should be the same size as the redo logs on the Primary.
Standby Redo Logs do not not to be multiplexed.
I would create SRL them on both the Primary and the Standby. Think of it as one database in either Standby or Primary Mode. If you have to switchover you still need them.
If you have SRL's setup and need to do either a failover or switchover it should occur faster and safer.
Best Regards
mseberg

Standby redo log does not exist...

Hello,
Oracle 11.2.0.2, running on Solaris
This is kind of a continuation of a previous thread, but this is a different question:
I have a DG configuration, with the primary database having 2 redo logs per redo log group.
And, it has 2 redo logs for the standby redo log groups.
But I just found out something very strange:
For the standby redo log group, even though the database shows it has two redo log files per group, the second file does not actually exist on the file system.
And, I have no idea where it is, or why the database is not complaining about it.
See below:
SQL> select * from v$logfile;
         GROUP# STATUS    TYPE    MEMBER                                        IS_
             11           STANDBY /opt/oracle/oradata2/PROD/REDO01A_STDBY.log NO
             11           STANDBY /opt/oracle/oradata3/PROD/REDO01B_STDBY.log NO    <== does not exist on file system
             12           STANDBY /opt/oracle/oradata2/PROD/REDO02A_STDBY.log NO
             12           STANDBY /opt/oracle/oradata3/PROD/REDO02B_STDBY.log NO    <== does not exist on file system
             13           STANDBY /opt/oracle/oradata2/PROD/REDO03A_STDBY.log NO
             13           STANDBY /opt/oracle/oradata3/PROD/REDO03B_STDBY.log NO    <== does not exist on file system
             14           STANDBY /opt/oracle/oradata2/PROD/REDO04A_STDBY.log NO
             14           STANDBY /opt/oracle/oradata3/PROD/REDO04B_STDBY.log NO    <== does not exist on file system
             15           STANDBY /opt/oracle/oradata2/PROD/REDO05A_STDBY.log NO
             15           STANDBY /opt/oracle/oradata3/PROD/REDO05B_STDBY.log NO    <== does not exist on file system
              5           ONLINE /opt/oracle/oradata1/PROD/REDO05A.log       NO
              5           ONLINE /opt/oracle/oradata2/PROD/REDO05B.log       NO
              6           ONLINE /opt/oracle/oradata1/PROD/REDO06A.log       NO
              6           ONLINE /opt/oracle/oradata2/PROD/REDO06B.log       NO
              7           ONLINE /opt/oracle/oradata1/PROD/REDO07A.log       NO
              7           ONLINE /opt/oracle/oradata2/PROD/REDO07B.log       NO
              8           ONLINE /opt/oracle/oradata1/PROD/REDO08A.log       NO
              8           ONLINE /opt/oracle/oradata2/PROD/REDO08B.log       NO
18 rows selected.
Notice below that the "B" redo logs do not exist.
SQL> !ls -l /opt/oracle/oradata3/PROD/REDO01B_STDBY.log
/opt/oracle/oradata3/PROD/REDO01B_STDBY.log: No such file or directory
SQL> !ls -l /opt/oracle/oradata3/PROD/REDO02B_STDBY.log
/opt/oracle/oradata3/PROD/REDO02B_STDBY.log: No such file or directory
SQL> !ls -l /opt/oracle/oradata3/PROD/REDO03B_STDBY.log
/opt/oracle/oradata3/PROD/REDO03B_STDBY.log: No such file or directory
SQL> !ls -l /opt/oracle/oradata3/PROD/REDO04B_STDBY.log
/opt/oracle/oradata3/PROD/REDO04B_STDBY.log: No such file or directory
SQL> !ls -l /opt/oracle/oradata3/PROD/REDO05B_STDBY.log
/opt/oracle/oradata3/PROD/REDO05B_STDBY.log: No such file or directory
But here, you can see that the "A" redo logs actually do exist.
SQL> !ls -l /opt/oracle/oradata2/PROD/REDO01A_STDBY.log
-rw-r-----   1 oracle   dba      536871424 Jan 7 2011 /opt/oracle/oradata2/PROD/REDO01A_STDBY.log

Hello;
I'm able to recreate
SQL> select * from v$logfile;
    GROUP# STATUS TYPE    MEMBER                                             IS_
         3         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_3_8gtxxrl6_.log
         2         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_2_8gtxxr4f_.log
         1         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_1_8gtxxqng_.log
         4         STANDBY /u01/app/oracle/oradata/RECOVER2/redo04.log        NO
         5         STANDBY /u01/app/oracle/oradata/RECOVER2/redo05.log        NO
         6         STANDBY /u01/app/oracle/oradata/RECOVER2/redo06.log        NOAnd then
SQL> !ls -al /u01/app/oracle/oradata/RECOVER2/redo04.log
ls: /u01/app/oracle/oradata/RECOVER2/redo04.log: No such file or directoryChecking... *Not there, but Oracle ( 11.2.0.3 ) allows clean up without barking. Had only one member so I did GROUP drop.
SQL> ALTER DATABASE DROP LOGFILE GROUP 4;
Database altered.
SQL> select * from v$logfile;
    GROUP# STATUS TYPE    MEMBER                                             IS_
         3         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_3_8gtxxrl6_.log
         2         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_2_8gtxxr4f_.log
         1         ONLINE /u01/app/oracle/flash_recovery_area/RECOVER2/onlin YES
                           elog/o1_mf_1_8gtxxqng_.log
         5         STANDBY /u01/app/oracle/oradata/RECOVER2/redo05.log        NO
         6         STANDBY /u01/app/oracle/oradata/RECOVER2/redo06.log        NO
SQL> Best Regards
mseberg

Standby Redo Log just sits as IN-MEMORY

Hi, I have shipped an archived redo log from my Primary to my physical standby.
I can see the log arriving at my Standby and being applied
select thread#, max(sequence#) "Last Standby Seq Received"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;
returns
   THREAD# Last Standby Seq Received
         1                       151
select thread#, max(sequence#) "Last Standby Seq Applied"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
and applied='YES'
group by thread# order by 1;
   THREAD# Last Standby Seq Applied
         1                      150
select stamp,name,applied
from v$archived_log
where applied != 'YES'
    STAMP
NAME
APPLIED
827498375
/home/app/oracle/fast_recovery_area/STANDBYL/archivelog/2013_09_30/o1_mf_1_151_9
4lrqpj3_.arc
IN-MEMORY
This log continually sits like this
I know that Redo Appply is active
select * from v$managed_standby where process = 'MRP0';
PROCESS          PID STATUS       CLIENT_P
CLIENT_PID
CLIENT_DBID
GROUP#                                   RESETLOG_ID    THREAD# SEQUENCE#
    BLOCK#     BLOCKS DELAY_MINS KNOWN_AGENTS ACTIVE_AGENTS
MRP0            3068 APPLYING_LOG N/A
N/A
N/A
N/A                                        820252586          1        152
      5038     102400          0            3             3
It looks as if 151 has been applied - yet
select thread#, max(sequence#) "Last Standby Seq Applied"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
and applied='YES'
group by thread# order by 1;
still shows 150 !
151 is not that big, I still would have expected it to have applied by now ( in excess of 30 mins )
Also I know there is no defer or time delay on the archive_destination setting on the Primary.
Any ideas why this standby redo log just sits IN-MEMORY ?
thanks,
Jim

Hello;
Not able to reproduce issue. Using Oracle 11.2.0.3 without Real-time apply.
select thread#, max(sequence#) "Last Standby Seq Received"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;
THREAD#                Last Standby Seq Received
1                      194
select thread#, max(sequence#) "Last Standby Seq Applied"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
and applied='YES'
group by thread# order by 1;
THREAD#                Last Standby Seq Applied
1                      194
select thread#, max(sequence#) "Last Standby Seq Applied"
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
And Applied='YES'
group by thread# order by 1;
THREAD#                Last Standby Seq Applied
1                      194
SELECT ARCH.THREAD# "Thread", ARCH.SEQUENCE# "Last Sequence Received", APPL.SEQUENCE# "Last Sequence Applied"
FROM
(SELECT THREAD# ,SEQUENCE# FROM V$ARCHIVED_LOG WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$ARCHIVED_LOG GROUP BY THREAD#)) ARCH,
(SELECT THREAD# ,SEQUENCE# FROM V$LOG_HISTORY WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$LOG_HISTORY GROUP BY THREAD#)) APPL
WHERE
Arch.Thread# = Appl.Thread#
ORDER BY 1;
Thread                 Last Sequence Received Last Sequence Applied
1                      194                    194
select * from v$managed_standby where process = 'MRP0';
( shows the next sequence 195 on mine )
Is it possible the Standby has one extra archive? I've noticed that sometime you will see one extra on that side which appears to have nothing to do with the Data Guard process.
Best Regards
mseberg

Standby Redo log creation

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