May 21, 2014 enabling archive log mode in rac oracle 11g. Jul 29, 2009 method to drop and recreate online redolog files with 2 members to each group. How do i find out the redo log file max size in oracle 11r2. The following statement drops redo log group number 3. Introduced with oracle asm 11g release 2, oracle asm cluster file system.
How to resize the online redologs on a rac environment. Recovering after the loss of online redo log files. Either adding more groups or making the members larger until i have enough online redo log to get me through at least 1520 minutes of work without switching. I understand how the redo logs work in a single instance database. Move rac redo log files in asm burleson consulting. However, there are situations where you might want to create additional groups or members. Real application clusters, commonly abbreviated as rac, is oracles industryleading architecture for scalable and faulttolerant databases. Developers and dbas get help from oracle experts on. The file names for log file members are automatically generated. Most database administrators know that it is good practice to have at least three orl groups for the database. The only reason to force a log switch regularly, even when the redo log group is not full, is for archiving the redo on a regular schedule, not to improve performance.
Maximum availability architecture maa data guard 10g setup guide creating a rac physical standby for a rac primary overview oracle maximum availability architecture maa 1 is oracles best practices blueprint based on proven oracle highavailability technologies and recommendations. Install dbeac and configure service groups first stage. You must create two redo log groups for each instance and all redo groups must be. Oracle database how to bypass the redo log generation. Jan 30, 2017 a log switch occurs when lgwr stops writing to one redo log group and starts writing to another by default it happens automatically when the current redo log group fills sometimes we can manually to force switch a log file to make the currently active group inactive and available for redo log maintenance operations. Oracle insights by thomas kyte apress publications 6. Using the oracle asm cluster file system acfs on linux part 1.
In an oracle rac database, each instance must have at least two groups of redo log files. Rac redo log thread maintenance burleson oracle consulting. For example, if there are disk groups named data1 and data2, you can create a log file with a member in each disk group with the following sql statement. I have been trying to understand the concept of redo log threads in a rac environment. Nov 03, 20 create rac standby database for rac primary database dataguard, physical standby, primary, rac, rac primary, rac standby, standby this article speaks of creating a rac physical standby database for rac primary database. Redo log threads in real application clusters ask tom oracle. How to resize the online redo logfiles oracle rac dba. The redo that would otherwise be generated for the undo information is not created, but ultimately the logging mode of the target table is what will dictate whether redo is generated for the table or not. Pro oracle database 11g rac on linux provides fulllifecycle guidance on implementing oracle real application clusters in a linux environment. Feb 17, 2015 2 srvctl stop database d pub o immediate 3sql startup mount oracle instance started. Hi there, in a policy managed rac configuration with dataguard also in rac mode, sometimes it is getting hard to manage standby redo logs. Oracle alter database add logfile tips oracle database tips by donald burlesonjanuary 12, 2015 question.
Pro oracle database 11g rac on linux experts voice in. Oracle dataguard how to resize redo log and standby redo. Recovery of redo log file using log sequence number by rman. Ask tom redo log threads in real application clusters. For example, oracle asm traditional disk groups is still the. Resizing redo logs in a dataguard envrionment physical. A log switch occurs when lgwr stops writing to one redo log group and starts writing to another by default it happens automatically when the current redo log group fills sometimes we can manually to force switch a log file to make the currently active group inactive and available for redo log maintenance operations. Recovering after the loss of all members of an online redo log group.
If you want to specify their location and the file name format manually, you can do it as follows. Drop and recreate online redolog files oracle dba tips. Prior 11g r2, it is recommended to run the listener from the asm home and. However, all the redo log files must reside on shared storage. Im working with oracle 11r2 and i want to see the max size of my redo log files i didnt install oracle so im not aware of the configuration. Switchover and switchback simplied in oracle 12c toad world blog.
Usually we do resize when redolog switches happen too frequently. Ask tom redo log threads in real application clusters oracle. Oct 03, 2012 to drop online redo log group 1 that is in status current, generate an archive on the primary database by switching logfile, and then clear the current online redo log group on the standby database, drop it and recreate it with the required size as done for groups 2 and 3 earlier. It is not possible to resize the redo log or standby redo log srl dynamically.
Rac redo log thread maintenance burleson consulting. But i cannot find proper documentation anywhere that clearly explains what a redo log thread is and how the whole thing works in a rac setup. Oracle database 11g oracle real application clusters handbook. How to speed up data pump import by suppressing redo. Oracle tuning by donald k burleson rampant books 7. From time to time, after a relocate, you will not have the required standby redo thread on the standby and it cannot go to realtime apply but working the old way. The online redo log orl for oracle rac is slightly different than a singleinstance database. In this course, you will be introduced to the general features and capabilities of oracle database 11g release 1 for oracle real application clusters rac. Create rac standby database for rac primary database. How to resize online redo log files in rac database with asm. Jan 10, 2015 how to multiplex redo log files in oracle 11g. Switchover endofredo log thread 1 sequence 24469 has been fixed.
Moreover, try to query both sql commands that are written above after each time you add and drop redo log group to see if its addeddeleted successfully. Oracle rac archive log files oracle tips by burleson consulting. Now we need to convert the single instance database to rac. Rac tuning for redo logs burleson oracle consulting. When you use dbca to create the database, dbca allocates redo log files to instances, as required, automatically. Can free right 2014 utrecht lapis mirrors elgato suspensa red price broken.
Oracle 9i10g11g dba handbook oracle press tata mcgrahill in india 5. Managing the oracle real application clusters guard log files. Ault is one of the worlds most famous oracle authors with over 20 books inprint, and madhu tumma is a recognized oracle10g grid and rac expert. For example, adding groups to a redo log can correct redo log group availability problems. In recovery mode, the instance performing the recovery must be able to read and process all the redo threads for the database, regardless of which instance generated.
In an oracle rac database, each instance requires its own set of redo log groups, which is known as a redo thread. I have two groups of redo logs that i want to resize. Group 3 u01oracleredofile3a, u02oracleredofile3b size 50m. How to resize redo on rac instance with asm option helioss. As with all rules of thumb there will be times when 1520 minutes is too long and too short. This is an excerpt from the landmark book oracle rac performance tuning.
Managing standby redologs in policy managed rac configuration. I needed to resize the redo log as it takes about 4 days to do a log switch. If you have a 100 log switches an hour with 50mb redo logs, you need e. Dec 12, 2015 tuning online redo logs in a rac environment. The recommended log switch frequency is at least once an hour. Cluster file system in an oracle 11g release 2 rac database on the. All partially created redo log files, created because of a system error, are automatically deleted. Find out how to prepare your hardware, deploy oracle real application clusters, optimize data integrity, and integrate seamless failover protection. Oct 23, 2012 to add or resize redo logfiles in a rac steps are. If a media failure damages all members of an online redo log group, then different scenarios can occur depending on the type of online redo log group affected by the failure and the archiving mode of the database. Crs log, listener log, oracle log, rac log if you are using rac system doesnt matter how many nodes you have you need to know where log files are located.
So while adding redolog group, we need to mention the thread parameter. Oracle database 11g oracle real application clusters handbook, second edition has been fully revised and updated to cover the latest tools and features. Dec 21, 2009 redo group 3 is active on instance 2 and instance acts as recovery instance once instance 2 is down, therefore redo group 1 is active on instance 2. Mar 02, 2008 resizing the online redologs on a rac environment is a simple task, that require a little more attention than that of a single instance. When do i use the alter database add logfile to add an online redo log can i use the alter database add logfile when adding a logfile group. Mar 05, 20 how to resize redo log and standby redo log in oracle dataguard environment. Can frosch old ng medicine zeina working senderos cartoon 1. Asm, how to resize redo on rac in this post, i try to explain how we can resize redolog files on rac instance while we have asm. Plan the redo log of a database and create all required groups and members of redo log files during database creation. May 08, 2012 if you have two diskgroup, you want to multiplex redo in different diskgroup, you just add redo log desitnation diskgroup. Sep 01, 2016 add drop redo log groups in oracle rac. Oct 09, 2014 how to resize online redo log files in rac database with asm option database setup has 2 nodes 11.
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