Drop and recreate online redolog files oracle dba tips. Add a member to a redo group oracle i have two redo log group with one member for each. The projected storage requirement for database is close to 750gb with datafiles, index, tablespaces at 700gb and control, redo, archive log files put together at 50gb we. Rac redo log thread maintenance burleson oracle consulting. In an oracle rac database, each instance must have at least two groups of redo log files. Jan 30, 2017 now the current redo log file will turns into active redo log file which means that file information are written into archive log through arcn once that written process is over an archive log then it turns into inactive redo log file creating group and member in redo log. You can find a step by step description of the procedure on this document.
So far as i know there is no fix for corrupted online redo log. Continue the above process until all logfile groups are moved to their new disk volumes. This article explains the steps for multiplexing redologs in oracle rac. Even the db is in archivelog mode you can do nothing if the redo log is corrupted. Ask tom redo log threads in real application clusters oracle. Hi tom, on reading oracle document, there information about adding new log group is. How to resize redo log and standby redo log in oracle dataguard environment. First, i determine the file names of the existing members. Adding a standby redo log file to standby database.
I understand how the redo logs work in a single instance database. In an oracle rac environment, the redo logs must be accessible from all. How to resize the online redologs on a rac environment. To get immediate access to the code depot of working rac scripts, buy it directly from the publisher and save more than 30%. How to resize the online redo logfiles single instance. It is not possible to resize the redo log or standby redo log srl dynamically.
However, the group number must be between 1 and maxlogfiles. Jul 29, 2009 method to drop and recreate online redolog files with 2 members to each group. Rac and grid infrastructure administration exam 1z0068 and become oracle certified expert. Premature redo log switching in oracle rac stack overflow. 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. Use this query to show group, thread rac node and member. Revealing the secrets for quickly implementing and tuning oracle rac database systems, this book covers all areas of oracle real application clusters including oracle10g new features. I have also experience in oracle apps with oracle certified apps dba for 11i status. What are the possible causes of premature redo log switching in oracle other than reaching the specified file size and executing alter system switch logfile we have a situation where some but not all of our nodes are prematurely switching redo log files before filling up. May 08, 2012 if you have two diskgroup, you want to multiplex redo in different diskgroup, you just add redo log desitnation diskgroup. 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. I have been trying to understand the concept of redo log threads in a rac environment. So while adding redolog group, we need to mention the thread parameter.
Pro oracle database 11g rac on linux experts voice in. Ask tom redo log threads in real application clusters. This is the book for anybody who want to learn oracle 11g rac. Jun 29, 2009 in a dataguard environment, if online redologs are resized, the standby logs also need to be resized to match the online redo logs in the primary database. Real application clusters, commonly abbreviated as rac, is oracles industryleading architecture for scalable and faulttolerant databases. How oracle rac redo and rollback are managed logicalread. Projected rac scalability for up to 17 nodes and 10,000 users. The book has illustrated every step in dealing with oracle rac, right from installation, managing, performance tuning and trouble shooting. To protect against failure of the redo logs, oracle allows redo logs to be multiplexed. This book includes scripts and tools to hypercharge oracle 11g. Add the standby logs with same size as primary online redologs. How to resize redo on rac instance with asm option. 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 the landmark book advanced oracle sql tuning the definitive reference is filled with valuable information on oracle sql tuning. Migrate data in realtime from oci classic to oci using mv2adb and oracle cloud.
Build your own oracle rac 11g cluster on oracle enterprise. With multiplexed redo logs two or more identical copies can be placed in separate locations. I have worked on multiple operating systems including aix, solaris, linux and windows. Add or drop inactive online redo log files searchoracle. Rather, the control files of the associated database are updated to drop the members of the group from the database structure. Maintaining standby database as rac with active dataguard and a realtime apply feature allows using it for reading, backup, and testing by converting it over to a snapshot standby database and back after the completion. Oracle cloud marketplace goldengate classic environment april 19, 2020.
If you do not specify the instance when adding the redo log group, then the redo log group is added to the instance to which you are currently connected. Plan the redo log of a database and create all required groups and members of redo log files during database creation. Covering all areas of oracle grid computing, this book is indispensable for any oracle dba who is charged with configuring and implementing oracle grid with server blades. Oracle goldengate on oracle cloud marketplace part 3 april 19, 2020 oracle goldengate on oracle cloud marketplace part 2 april 19, 2020 data migration to autonomous database using mv2adb april 19, 2020. If online redologs are resized, the standby logs also need to be resized to match the online redo logs in the primary database. We are going to add our new redo file by below command. Do not skip redo log file group numbers that is, do not number your groups 10, 20, 30, and so on, or you will consume unnecessary space in the control files of the database. With the group removed, add the group anew in the new location alter database add logfile command. I very highly recommend this book for every oracle dba dealing with rac. Migration of a vldb to rac 11g with minimal downtimedotan mor, senior dba pelephone dba teamdotan will tell us the whole story of migrating an 8tb datawarehouse. Versastack solution by cisco and ibm with oracle rac, ibm. I have two groups of redo logs that i want to resize. In rac one node configuration, a single instance of oracle rac database runs on.
Oct 23, 2012 to add or resize redo logfiles in a rac steps are. In particular the section titled recovering after losing of all members of an online redo log group. Apr 19, 2010 to protect against failure of the redo logs, oracle allows redo logs to be multiplexed. Continue the above process until all logfile groups are moved to. Thatswhy it is recommended to multiplex the redo groups. The source and target databases are 2node oracle rac 11gr2. Oracle grid and rac is the firstofitskind reference for oracle grid computing. Before resize each thread was having 3 redo log groups with 1 member of 50mb in each group. If you have a 100 log switches an hour with 50mb redo logs, you need e. How to sync standby database which is lagging behind from primary database.
Oracle rac archive log files oracle tips by burleson consulting. Now the current redo log file will turns into active redo log file which means that file information are written into archive log through arcn once that written process is over an archive log then it turns into inactive redo log file creating group and member in redo log. Remove thread parameter from your pfilespfile as soon as possible before the next server restart. Recreate online redo logs and standby logs oracle dba. We wish to setup oracle 11g rac on windows 2003 r2 server platform with asm using this san storage. However, there are situations where you might want to create additional groups or members. In an oracle rac database, each instance requires its own set of redo log groups, which is known as a redo thread.
Log directory structure in cluster ready services to diagnose any problem, the first thing examined by oracle support are the installation log files. How to resize the online redo logfiles oracle rac dba. It is similar to that of multiplexing in standalone, only change is rac will have threads for node. Switch until we are into log group 5,6,7,8 so we can drop log groups 1, 2,3 and 4. Managing the redolog in oracle11g ampersand academy. In a rac real application clusters environment you have to specify which instance the redo log group will belong to by setting thread number. 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. How to resize online redo log files in rac database with. I have been oracle certified dba since version 7 till 11g along with certified expert on 10g rac.
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. See the oracle database backup and recovery users guide. Aug 15, 2007 next, drop the online redo log with the alter database drop logfile group x command. 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. 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. This book was produced by a team of specialists from around the world working at the cisco. I am working as oracle architectconsultant for last 16 years. I needed to resize the redo log as it takes about 4 days to do a log switch. Disabling an old rac instance thread the great grandson. Oracle database 11g oracle real application clusters. Would like to add a few things here in the context of rac. The recommendation is to have log switches occur a few times an hour.
Take care to add all the new larger groups, then switch over until the current redolog for each instance is on the new larger groups before starting to remove the old groups. How to resize online redo log files in rac database with asm. 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. 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 the redo thread. To get immediate access to the code depot of working rac scripts, buy it directly from. The recommended log switch frequency is at least once an hour. 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. Mar 05, 20 how to resize redo log and standby redo log in oracle dataguard environment. How to resize redo on rac instance with asm option helioss. Your course of action will depend on other factors you can read about in the documentation. Hello team, we have netapp fas3140 clustered san storage in our environment.
Pro oracle database 11g rac on linux provides fulllifecycle guidance on implementing oracle real application clusters in a linux environment. Every instance in a rac database has a thread number. Dbca, running on oracle zone, pops up out of memory. How to add or increase the size of redo log files in rac. If you have two diskgroup, you want to multiplex redo in different diskgroup, you just add redo log desitnation diskgroup. When a redo log group is dropped from the database, and you are not using the oracle managed files feature, the operating system files are not deleted from disk.
Mar 02, 2008 take care to add all the new larger groups, then switch over until the current redolog for each instance is on the new larger groups before starting to remove the old groups. Using group numbers can make administering redo log groups easier. Next, drop the online redo log with the alter database drop logfile group x command. Oracle grid book rac clusters dba book rampant books. Sep 01, 2016 steps to add redo log groups to oracle rac setup. Oct 30, 20 in a rac real application clusters environment you have to specify which instance the redo log group will belong to by setting thread number. The online logs on the standby side will be created at switchover time so no.
This book is a master piece on oracle 11g rac by mr. Redo log files were created in the redo01dg and redo02dg disk groups. Anyone who knows anything about database administration knows the importance of the dump directories bdump, udump, and cdump. Each database consists of two or more redo log files. Apr 19, 2011 i am working as oracle architectconsultant for last 16 years. Recovering after the loss of all members of an online redo log group. Group 3 u01oracle redofile3a, u02oracleredofile3b size 50m. Advanced configuration oracle rac idataagent books online. Disabling an old rac instance thread the great grandson of. However, the recommended number of standby redo log file groups is dependent on the number of threads on the primary database. Rac redo log thread maintenance burleson consulting. Oracle 11g oracle 12c rac oracle standby oracle goldengate mongodb postgresdb. Create these redo log groups and establish group members. Oracle dataguard how to resize redo log and standby redo.
How to multiplex redo log files in oracle 11g blogger. To create a new group of redo log files, use the sql statement alter database with the add logfile clause. The information in this guide is not validated by oracle, is not supported by oracle, and should only be used at your own risk. Build your own oracle rac 11g cluster on oracle enterprise linux and iscsi, page 3. However, all the redo log files must reside on shared storage. To add a redo log group to a specific instance, specify the instance clause in the alter database add logfile statement. Multiplexing means to keep multiple copies of redo log in different diskgroup. Recovering after the loss of online redo log files. For example, adding groups to a redo log can correct redo log group availability problems.
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