Number of Standby Redo Logs on Standby Database

Hello All:
Per various docs i calculated and created the number of standby redo logs.
I created 6 standby redo logs in addition to 3 online.
However, i always see only two standby redo logs being used. Any ideas?
Thanks
San~

try:
alter system archive log current;
and get information:
select * from v$logfile;
select * from v$log;
Thanks.

Similar Messages

When is anything written to standby redo logs on standby database?

I am on Oracle 10.2.0.4 on HP UNIX. I have read Oracle 10.2 concepts guide on technet.oracle.com, have read may article on metalink and internet, yet I am unable to verify when anything is written to standby redo logs on stand by database.
I have a simple database reconfiguration: a primary database and one standby database.
I created primary database and set up log_archive_dest_2 to use LGWR SYNC AFFIRM
I have created standby redo logs on primary.
alter database add standby logfile GROUP
I create standby control file on primary.
I copied all the primary information to create standby database. I have put standby database in managed recovery.
I did archive log switches, I created a table and inserted information in table.
I never saw standby redo logs updated on standby database by looking at timestamp of standby redo log files.
I then setup database in maximum availability mode by running following on primary:
Alter database set standby database to maximize availability
When I do insert into my tables, I do see standby redo log files on primary database being updated, but I have never seen standby redo logs on standby database updated. Why?
I am still at loss when actually standby redo logs are updated on standby database.
When I read Oracle 9i database documentation on data guard, it says that you do not need standby redo logs on primary instead you need them on standby. Only reason, you need them on primary is from primary changes role to standby database, so standby redo logs on standby database should be updated instead of standby redo logs on primary.

What is the PROTECTION_MODE ,PROTECTION_LEVEL values of your database.
As per metalink:--
Create standby redo log files, if necessary:
Standby redo logs are necessary for the higher protection levels such as
Guaranteed, Instant, and Rapid. In these protection modes LGWR from the
Primary host writes transactions directly to the standby redo logs.
This enables no data loss solutions and reduces the amount of data loss
in the event of failure. Standby redo logs are not necessary if you are using
the delayed protection mode.
If you configure standby redo on the standby then you should also configure
standby redo logs on the primary database. Even though the standby redo logs
are not used when the database is running in the primary role, configuring
the standby redo logs on the primary database is recommended in preparation
for an eventual switchover operation.
Standby redo logs must be archived before the data can be applied to the
standby database. The standby archival operation occurs automatically, even if
the standby database is not in ARCHIVELOG mode. However, the archiver process
must be started on the standby database. Note that the use of the archiver
process (ARCn) is a requirement for selection of a standby redo log.
METALINK ID:- Doc ID: Note:219344.1
Edited by: Anand... on Sep 15, 2008 2:15 AM

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

Delete standby redo log from primary database

Hi all,
I'm trying to drop standby logfiles on primary database (other database that I'm configuring the DG).
The members of the standby log groups don't exists on file system.
Somebody have deleted these files. Its old configuration where the files were in file system. Now they are in ASM.
When I try to drop the standby logfiles I got the following error:
SQL> alter database clear logfile group 7;
alter database clear logfile group 7
ERROR at line 1:
ORA-19528: redo logs being cleared may need access to files
SQL> select * from v$logfile order by 1;
    GROUP# STATUS TYPE    MEMBER                                                                           IS_
         1         ONLINE +REDO1/proj/onlinelog/group_1.256.340558657                                     NO
         1         ONLINE +REDO2/proj/onlinelog/group_1.256.340558659                                     NO
         2         ONLINE +REDO1/proj/onlinelog/group_2.257.340558879                                     NO
         2         ONLINE +REDO2/proj/onlinelog/group_2.259.340558879                                     NO
         3         ONLINE +REDO1/proj/onlinelog/group_3.258.340558707                                     NO
         3         ONLINE +REDO2/proj/onlinelog/group_3.257.340558709                                     NO
         4         ONLINE +REDO2/proj/onlinelog/group_4.258.340558713                                     NO
         4         ONLINE +REDO1/proj/onlinelog/group_4.259.340558711                                     NO
         5         ONLINE +REDO2/proj/onlinelog/group_5.260.340558965                                     NO
         5         ONLINE +REDO1/proj/onlinelog/group_5.260.340558963                                     NO
         6         ONLINE +REDO1/proj/onlinelog/group_6.261.340558967                                     NO
         6         ONLINE +REDO2/proj/onlinelog/group_6.261.340558967                                     NO
         7         STANDBY /oracle/proj/onlinelog2/redo_702.log                                            NO
         7         STANDBY /oracle/proj/onlinelog1/redo_701.log                                            NO
         8         STANDBY /oracle/proj/onlinelog2/redo_802.log                                            NO
         8         STANDBY /oracle/proj/onlinelog1/redo_801.log                                            NO
         9         STANDBY /oracle/proj/onlinelog2/redo_902.log                                            NO
         9         STANDBY /oracle/proj/onlinelog1/redo_901.log                                            NO
        10         STANDBY /oracle/proj/onlinelog1/redo_1001.log                                           NO
        10         STANDBY /oracle/proj/onlinelog2/redo_1002.log                                           NO
20 rows selected.
SQL> select * from v$standby_log order by 1;
    GROUP# DBID            THREAD# SEQUENCE#      BYTES       USED ARC STATUS     FIRST_CHANGE# FIRST_TIM LAST_CHANGE# LAST_TIME
         7 UNASSIGNED            0          0 104854601        512 YES UNASSIGNED             0                      0
         8 UNASSIGNED            0          0 104854601        512 YES UNASSIGNED             0                      0
         9 UNASSIGNED            0          0 104854601        512 YES UNASSIGNED             0                      0
        10 UNASSIGNED            0          0 104854601        512 YES UNASSIGNED             0                      0What can I do to drop these reference?
Any other solution instead of edit the controlfile and stop/start tghe database?
thank you!!!!

Hello;
Well Oracle thinks the files are there, but I remember a bug on metalink where the controlfile still had them, but they were not on the file system. Can you confirm they exist?
Meanwhile I check my notes for the Oracle doc nunber.
Bug 6128242: TRYING TO DROP STANDBY LOG FAILS WITH ORA-19528
So if you are Oracle 10 this might be the issue.
workaround is to re-create the controlfile without the incorrect logfile. ( Yuk!! )
ORA-01156 When Adding Or Dropping Redo Logs [ID 452152.1]
Best Regards
mseberg
Edited by: mseberg on Oct 31, 2011 5:09 PM

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 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

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

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.

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

Adding online redo logs with standby database in place

Hi group,
I have decided to add one new member to my existing redo log groups and an additional redo log group to my primary database.
That change went ok without problems. I assumed that with standby_file_management=auto the equivalent online redo logs are created on the standby database. But this is not the case.
The documentation is unclear about this point and I did not find anything suitable on metalink. The docs suggest to cancel managed recovery on the standy, setting standby_file_management to MANUAL and then adding online logs, quote:
"To add an online redo log, use a SQL statement such as this:
SQL> ALTER DATABASE ADD STANDBY LOGFILE 'prmy3.log' SIZE 100K;"
This however - IMO - adds a new STANDBY redo log to the standby database, what I need is an ONLINE redo log.
Does anybody have some experience to share here?
Facts:
Solaris 8
Oracle 9.2.0.6
Thanks!
Martin

OK, for those who come across the same problem.
You need to create a new standby controlfile, copy it as well as any new online redo log from production to the standby environment.
Once the files are in place, start the standby as normal and open it read only to see if everything is ok:
startup nomount
alter database mount standby database;
alter database open read only
Only when there are no errors in your alert.log you are safe.
Martin

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

Data Guard : Standby Redo Log CONFUSION

Trying to set up test Standby db on 10.2.0
I am well confused about below step 3.1.3, how is the normal redo linked with standby redo, should standby not be members of orginal redo groups?
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703
Original redo logs:
SQL> select * from v$log;
    GROUP#    THREAD# SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME
         1          1         28   52428800          1 YES INACTIVE                375136 22-NOV-07
         2          1         29   52428800          1 YES INACTIVE                375138 22-NOV-07
         3          1         30   52428800          1 NO CURRENT                 375143 22-NOV-07I added below from notes:
ALTER DATABASE ADD STANDBY LOGFILE GROUP 10
('/u01/oracle/oradata/db01/redo01_stb.log') SIZE 50M;
ALTER DATABASE ADD STANDBY LOGFILE GROUP 11
('/u02/oracle/oradata/db01/redo02_stb.log') SIZE 50M;
ALTER DATABASE ADD STANDBY LOGFILE GROUP 12
('/u03/oracle/oradata/db01/redo03_stb.log') SIZE 50M;After few alter system switch logfile; I still have:
    GROUP#    THREAD# SEQUENCE# ARC STATUS
        10          0          0 YES UNASSIGNED
        11          0          0 YES UNASSIGNED
        12          0          0 YES UNASSIGNEDAll are UNASSIGNED, should one standby group not be ACTIVE like the above link shows.
Many think for any help

First things first:
From the Docs.:
"Minimally, the configuration should have one more standby redo log file group than the number of online redo log file groups on the primary database. However, the recommended number of standby redo log file groups is dependent on the number of threads on the primary database. Use the following equation to determine an appropriate number of standby redo log file groups:
(maximum number of logfiles for each thread + 1) * maximum number of threads
Using this equation reduces the likelihood that the primary instance's log writer (LGWR) process will be blocked because a standby redo log file cannot be allocated on the standby database. For example, if the primary database has 2 log files for each thread and 2 threads, then 6 standby redo log file groups are needed on the standby database."
You are 1 short!

Dataguard Solution for standby redo log file groups

Respected Experts,
My database version is 10.2.0.1.0 and Red Hat 5 os.I want to create a standby database using RMAN.
Can any one help me with the full steps.And i'm also confuse about number of standby redo log file members
need to be created.
Thanks and Regards
Monoj Das

My database version is 10.2.0.1.0 and Red Hat 5 os.I want to create a standby database using RMAN.To configure standby either you can use duplicate target database for standby
or
1) restore standby controlfile
2) mount standby database
3) restore database
and configure standby paraemter then start MRP, will do.
http://docs.oracle.com/cd/B19306_01/server.102/b14239/create_ps.htm
Can any one help me with the full steps.And i'm also confuse about number of standby redo log file members
need to be created.It depends which parameter you want to use, if you mention log_archive_dest_2='service ARCH ' then no need to create any standby redo log file groups,
If you use log_archive_dest_2='service LGWR ' here transport will be in terms of redo and you need standby redo log files on standby database. Which is realtime.
When you use LGWR, data lost will be less if in case of any online redo log file lost. which is recommended.
HTH.

How do look if i have Standby Redo Log files

How do look if i have Standby Redo Log files
example of creating them..

To check existence of Standby Redo Log Files:
SQL> v$standby_log
Name                                      Null?    Type
----------------------------------------- -------- ---------------------------- GROUP#                                             NUMBER
DBID                                               VARCHAR2(40)
THREAD#                                            NUMBER
SEQUENCE#                                          NUMBER
BYTES                                              NUMBER
USED                                               NUMBER
ARCHIVED                                           VARCHAR2(3)
STATUS                                             VARCHAR2(10)
FIRST_CHANGE#                                      NUMBER
FIRST_TIME                                         DATE
LAST_CHANGE#                                       NUMBER
LAST_TIME                                          DATE
SQL> select * from v$standby_log;
no rows selected
SQL>To Create a Standby Redo Log file:
SQL> alter database add standby logfile group 11 ('/u01/app/test.log') size 5m;
Database altered.
SQL> set line 10000
SQL> select * from v$standby_log;
    GROUP# DBID                                        THREAD# SEQUENCE#      BYTES       USED ARC STATUS     FIRST_CHANGE# FIRST_TIM LAST_CHANGE# LAST_TIME
        11 UNASSIGNED                                        0          0    5242880        512 YES UNASSIGNED              0                      0
SQL>and this is how you drop:
SQL> alter database drop standby logfile group 11;
Database altered.
SQL> ! rm /u01/app/test.log
SQL>Asif Momen
http://momendba.blogspot.com
Edited by: Asif Momen on Mar 16, 2010 1:32 PM
Included DROP example

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

Number of Standby Redo Logs on Standby Database

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