recommended OS size for redo log block

Similar Questions

• Waiting for redo log

  Hello
  in 10g R2 what are / can be the causes of waiting for redo log?
  
  Thank you.

  example of waiting for recovery logs causes may be:
  -does not redo groups (remember to add one more, if necessary)
  -low rate of I/O
  -Redo large log buffer (take a long time for the dump file data) - refers to the slow storage
  -application hurt writes, making many validations

  Run the Advisor of the ADDM, and see the recommendations. Look at the first 5 albums events. Maybe it's not relevant to DBTime?

• Waiting for redo log file missing when restore main database using RMAN backup that was taken on the database physical standby

  Here's my question after tons of research and test without have the right solutions.

  Target:

  (1) I have a 12.1.0.2 database unique main enterprise 'testdb' as database instance running on the server "node1".

  (2) I created physical standby database "stbydb" on the server "node2".

  (3) DataGuard running on the mode of MaxAvailability (SYNC) with roll forward in real time 12 default c apply.

  (4) primary database has 3 groups of one-man redo. (/oraredo/testdb/redo01.log redo02.log redo03.log)

  (5) I've created 4 standby redo logfiles (/oraredo/testdb/stby01.log stby02.log stby03.log stby04.log)

  (6) I do RMAN backup (database and archivelog) on the site of relief only.

  (7) I want to use this backup for full restore of the database on the primary database.

  He is a DR test to simulate the scenario that has lost every primary & Eve total servers.

  Here is how to save, on the database pending:

  (1) performance 'alter database recover managed standby database Cancel' to ensure that compatible data files

  (2) RMAN > backup database;

  (3) RMAN > backup archivelog all;

  I got elements of backup and copied to primary db Server something like:

  /Home/Oracle/backupset/o1_mf_nnndf_TAG20151002T133329_c0xq099p_.BKP (data files)

  /Home/Oracle/backupset/o1_mf_ncsnf_TAG20151002T133329_c0xq0sgz_.BKP (spfile & controlfile)

  /Home/Oracle/backupset/o1_mf_annnn_TAG20151002T133357_c0xq15xf_.BKP (archivelogs)

  So here's how to restore, on the main site:

  I clean all the files (data files, controlfiles oder all gone).

  (1) restore spfile from pfile

  RMAN > startup nomount

  RMAN > restore spfile from pfile ' / home/oracle/pfile.txt' to ' / home/oracle/backupset/o1_mf_ncsnf_TAG20151002T133329_c0xq0sgz_.bkp';

  (2) modify pfile to convert to db primary content. pFile shows below

  *.audit_file_dest='/opt/Oracle/DB/admin/testdb/adump '

  * .audit_trail = "db".

  * full = '12.1.0.2.0'

  *.control_files='/oradata/testdb/control01.ctl','/orafra/testdb/control02.ctl'

  * .db_block_size = 8192

  * .db_domain = "

  *.db_file_name_convert='/testdb/','/testdb /'

  * .db_name = "testdb".

  * .db_recovery_file_dest ='/ orafra'

  * .db_recovery_file_dest_size = 10737418240

  * .db_unique_name = "testdb".

  *.diagnostic_dest='/opt/Oracle/DB '

  * .fal_server = "stbydb".

  * .log_archive_config = 'dg_config = (testdb, stbydb)'

  * .log_archive_dest_2 = "service = stbydb SYNC valid_for = (ONLINE_LOGFILE, PRIMARY_ROLE) db_unique_name = stbydb'"

  * .log_archive_dest_state_2 = 'ENABLE '.

  *.log_file_name_convert='/testdb/','/testdb /'

  * .memory_target = 1800 m

  * .open_cursors = 300

  * runoff = 300

  * .remote_login_passwordfile = "EXCLUSIVE."

  * .standby_file_management = "AUTO".

  * .undo_tablespace = "UNDOTBS1.

  (3) restart db with updated file pfile

  SQLPLUS > create spfile from pfile='/home/oracle/pfile.txt'

  SQLPLUS > the judgment

  SQLPLUS > startup nomount

  (4) restore controlfile

  RMAN > restore primary controlfile to ' / home/oracle/backupset/o1_mf_ncsnf_TAG20151002T133329_c0xq0sgz_.bkp';

  RMAN > change the editing of the database

  (5) all elements of backup catalog

  RMAN > catalog starts by ' / home/oracle/backupset / '.

  (6) restore and recover the database

  RMAN > restore database;

  RMAN > recover database until the SNA XXXXXX; (this YVERT is the maximum in archivelog backups that extends beyond the scn of the backup of the data file)

  (7) open resetlogs

  RMAN > alter database open resetlogs;

  Everything seems perfect, except one of the file log roll forward pending is not generated

  SQL > select * from v$ standby_log;

  ERROR:

  ORA-00308: cannot open archived log ' / oraredo/testdb/stby01.log'

  ORA-27037: unable to get file status

  Linux-x86_64 error: 2: no such file or directory

  Additional information: 3

  no selected line

  I intended to use the same backup to restore primary basic & helps record traffic and the downtime between them in the world of real output.

  So I have exactly the same steps (except STANDBY restore CONTROLFILE and not recover after database restore) to restore the database pending.

  And I got the same missing log file.

  The problem is:

  (1) complete alert.log filled with this error, not the concern here

  (2) now repeat it in real time apply won't work since the Party shall LGWR shows always "WAITING_FOR_LOG."

  (3) I can't delete and re-create this log file

  Then I tried several and found:

  The missing standby logfile was still 'ACTIVE' at present RMAN backup was made.

  For example, on db standby, under Group #4 (stby01.log) would be lost after the restoration.

  SQL > select GROUP #, SEQUENCE #, USE (s), the STATUS from v$ standby_log;

  GROUP # SEQUENCE # USED STATUS

  ---------- ---------- ---------- ----------

  4 19 ACTIVE 133632

  5 0 0 UNASSIGNED

  6 0 0 not ASSIGNED

  7 0 0 UNASSIGNED

  So until I take the backup, I tried on the primary database:

  SQL > alter system set log_archive_dest_state_2 = delay;

  This was the Group of standby_log side Eve #4 was released:

  SQL > select GROUP #, SEQUENCE #, USE (s), the STATUS from v$ standby_log;

  GROUP # SEQUENCE # USED STATUS

  ---------- ---------- ---------- ----------

  4 0 0 UNASSIGNED

  5 0 0 UNASSIGNED

  6 0 0 not ASSIGNED

  7 0 0 UNASSIGNED

  Then, the backup has been restored correctly without missing standby logfile.

  However, to change this primary database means break DataGuard protection when you perform the backup. It's not accept on the production environment.

  Finally, my real questions come:

  (1) what I do may not do on parameter change?

  (2) I know I can re-create the control file to redo before delete and then recreate after. Is there any simple/fast to avoid the standby logfile lost or recreate the lost one?

  I understand that there are a number of ways to circumvent this. Something to keep a copy of the log file waiting restoration progress and copy up one missing, etc, etc...

  And yes I always have done no real-time applies "to the aid of archived logfile" but is also not accept mode of protection of production.

  I just want proof that the design (which is displayed in a few oracle doc Doc ID 602299.1 is one of those) that backs up data backup works effectively and can be used to restore the two site. And it may be without spending more time to resume backups or put the load on the primary database to create the database before.

  Your idea is very much appreciated.

  Thank you!

  Hello

  1--> when I take via RMAN backup, RMAN does not redo log (ORL or SRL) file, so we cannot expect ORLs or SRL would be restored.

  2nd--> when we opened the ORL database should be deleted and created

  3rd--> Expecting, SRL should not be an issue.we should be able to do away with the fall.

  DR sys@cdb01 SQL > select THREAD #, SEQUENCE #, GROUP #, STATUS from v$ standby_log;

  THREAD # SEQUENCE # GROUP # STATUS

  ---------- ---------- ---------- ----------

  1 233 4 ACTIVE

  1 238 5 ACTIVE

  DR sys@cdb01 SQL > select * from v$ logfile;

  GROUP # STATUS TYPE MEMBER IS_ CON_ID

  ---------- ------- ------- ------------------------------ --- ----------

  3 /u03/cdb01/cdb01/redo03.log no. 0 online

  /U03/cdb01/cdb01/redo02.log no. 0 2 online

  1 /u03/cdb01/cdb01/redo01.log no. 0 online

  4 /u03/cdb01/cdb01/stdredo01.log WATCH No. 0

  /U03/cdb01/cdb01/stdredo02.log EVE 5 No. 0

  DR sys@cdb01 SQL > ! ls - ltr /u03/cdb01/cdb01/stdredo01.log

  method: cannot access the /u03/cdb01/cdb01/stdredo01.log: no such file or directory

  DR sys@cdb01 SQL >! ls - ltr /u03/cdb01/cdb01/stdredo02.log

  -rw - r-. 1 oracle oinstall 52429312 17 Oct 15:32 /u03/cdb01/cdb01/stdredo02.log

  DR sys@cdb01 SQL > alter database force claire logfile 4;

  change the database group claire logfile 4

  *

  ERROR on line 1:

  ORA-01156: recovery or current flashback may need access to files

  DR sys@cdb01 SQL > alter database recover managed standby database cancel;

  Database altered.

  DR sys@cdb01 SQL > change the database group claire logfile 4;

  Database altered.

  DR sys@cdb01 SQL > ! ls - ltr /u03/cdb01/cdb01/stdredo01.log

  -rw - r-. 1 oracle oinstall 52429312 17 Oct 15:33 /u03/cdb01/cdb01/stdredo01.log

  DR sys@cdb01 SQL >

  If you do, you can recreate the controlfile without waiting for redo log entry...

  If you still think it's something is not acceptable, you must have SR with support to analyze why he does not abandon SRL when controlfile_type is "underway".

  Thank you

• waiting for redo log deleted

  Oracle 11 g 2 (11.2.0.3) Linux x86_64

  A silly mistake was made. While recreate redo standby logfiles, I managed to remove (rm command) waiting for redo log file in progress (before the end of the application) of the BONE. Now I see in the log of alerts:

  ORA-00313: open failed for members of log group 7 of thread 1
  ORA-00312: online log 7 thread 1: ..../standby_redo7.log'
  ORA-27037: unable to obtain file status
  Linux-x86_64 Error: 2: No such file or directory
  Additional information: 3
  

  What are my options at this point? I have to any cancelled transaction? The settlement seems to be moving right on the property. Where am I people?

  Thanks to you all.

  Hello

  1 ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

  2. ALTER LOGFILE GROUP 7 CLEAR DATABASE;

  3 ALTER DATABASE DROP STANDBY LOGFILE GROUP 7;

  4. ALTER DATABASE ADD STANDBY LOGFILE GROUP 7;  OR ALTER DATABASE ADD LOGFILE MEMBER '' HELPS GROUP 7;

  5. START AGAIN APPLY: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CURRENT LOGFILE USING DISCONNECT FROM THE SESSION;

  HTH

  Tobi

• I have to create the new group for waiting for redo log files?

  I have 10 group of files redo log with 2 members of each group for my primary database, I need to create new group for redo log files for the database of relief pending

  Group # members

  ==============

  1              2

  2              2

  3             2

  4             2

  5             2

  6             2

  7             2

  8             2

  9             2

  2 of 10

  If so, the following statement is correct? or nto

  ALTER DATABASE ADD STANDBY LOGFILE GROUP 1 ('D:\Databases\epprod\StandbyRedoLog\REDO01.) LOG',D:\Databases\epprod\StandbyRedoLog\REDO01_1.log');

  Please correct me if am doin wrong

  because when I run the statement I have error message saying: the group is already created.

  Thanks John

  I just found the answer

  Yes, it of recomeded to add the new group, for instnace if I have 10 group of 1 to 10, then the wait should be from 11 to 20

  Thanks I found the answer.

• ORA-00368: checksum error in redo log block

  Hi all
  
  
  We have two node RAC instance.
  11 GR 1 material [11.1.0.7] with R12.1.3 Apps
  
  
  In the two journal alerts nodes with errors such as:
  ORA-00368: checksum error in redo log block
  ORA-00353: journal corruption near block 163842 change 3809154858 time 03/31/2013 16
  : 30: 29
  ORA-00334: archived log: ' / arch/1_19685_696638733.dbf '
  ORA-00700: soft internal error, arguments: [kesqsMakeSql - invstat:cpuTime], [],]
  ], [], [], [], [], []
  
  IAM see this error frequently,
  Please help me solve the problem.
  
  
  Thank you
  Shaik

  Shaik wrote:
  Hi Hussein.

  I checked, not applied the patch.

  Thank you
  Shaik

  Please apply the patch and see if you see the same entries in the log file.

  Thank you
  Hussein

• optimal size of redo log

  Hi all
  
  Recently we migrated 9.2.0.4 to 10.2.0.4 and performance of the database is slow in a newer version, log alerts of the audit, we found that: -.
  
  Thread 1 cannot allocate new logs, Checkpoint 1779 sequence is not complete
  Currently Journal # 6 seq # 1778 mem # 0: /oradata/lipi/redo6.log
  Currently Journal # 6 seq # 1778 mem # 1: /oradata/lipi/redo06a.log Wed Mar 10 15:19:27 2010 1 thread forward to log sequence 1779 (switch LGWR)
  Currently journal # 1, seq # 1779 mem # 0: /oradata/lipi/redo01.log
  Currently journal # 1, seq # 1779 mem # 1: /oradata/lipi/redo01a.log Wed Mar 10 15:20:45 2010 1 thread forward to log sequence 1780 (switch LGWR)
  Currently Journal # 2 seq # 1780 mem # 0: /oradata/lipi/redo02.log
  Currently Journal # 2 seq # 1780 mem # 1: /oradata/lipi/redo02a.log Wed Mar 10 15:21:44 2010 1 thread forward to log sequence 1781 (switch LGWR)
  Currently Journal # 3 seq # 1781 mem # 0: /oradata/lipi/redo03.log
  Currently Journal # 3 seq # 1781 mem # 1: /oradata/lipi/redo03a.log Wed Mar 10 15:23 2010 Thread 1 Advanced to save sequence 1782 (switch LGWR)
  Currently Journal # 4, seq # 1782 mem # 0: /oradata/lipi/redo04.log
  Currently Journal # 4, seq # 1782 mem # 1: /oradata/lipi/redo04a.log Wed Mar 10 15:24:48 2010 1 thread forward to log sequence 1783 (switch LGWR)
  Currently journal # 5 seq # 1783 mem # 0: /oradata/lipi/redo5.log
  Currently journal # 5 seq # 1783 mem # 1: /oradata/lipi/redo05a.log Wed Mar 10 15:25 2010 1 thread cannot allocate new journal, sequence 1784 Checkpoint ends not
  Currently journal # 5 seq # 1783 mem # 0: /oradata/lipi/redo5.log
  Currently journal # 5 seq # 1783 mem # 1: /oradata/lipi/redo05a.log Wed Mar 10 15:25:27 2010 1 thread forward to log sequence 1784 (switch LGWR)
  Currently Journal # 6 seq # 1784 mem # 0: /oradata/lipi/redo6.log
  Currently Journal # 6 seq # 1784 mem # 1: /oradata/lipi/redo06a.log Wed Mar 10 15:28:11 2010 1 thread forward to log sequence 1785 (switch LGWR)
  Currently journal # 1, seq # 1785 mem # 0: /oradata/lipi/redo01.log
  Currently journal # 1, seq # 1785 mem # 1: /oradata/lipi/redo01a.log Wed Mar 10 15:29:56 2010 1 thread forward to log sequence 1786 (switch LGWR)
  Currently Journal # 2 seq # 1786 mem # 0: /oradata/lipi/redo02.log
  Currently Journal # 2 seq # 1786 mem # 1: /oradata/lipi/redo02a.log Wed Mar 10 15:31:22 2010 1 wire could not be allocated for new newspapers, private part of 1787 flush sequence is not complete
  Currently Journal # 2 seq # 1786 mem # 0: /oradata/lipi/redo02.log
  Currently Journal # 2 seq # 1786 mem # 1: /oradata/lipi/redo02a.log Wed Mar 10 15:31:29 2010 1 thread forward to log sequence 1787 (switch LGWR)
  Currently Journal # 3 seq # 1787 mem # 0: /oradata/lipi/redo03.log
  Currently Journal # 3 seq # 1787 mem # 1: /oradata/lipi/redo03a.log Wed Mar 10 15:31:40 2010 1 thread cannot allocate a new journal, sequence 1788 Checkpoint ends not
  Currently Journal # 3 seq # 1787 mem # 0: /oradata/lipi/redo03.log
  Currently Journal # 3 seq # 1787 mem # 1: /oradata/lipi/redo03a.log Wed Mar 10 15:31:47 2010 1 thread forward to log sequence 1788 (switch LGWR)
  Currently Journal # 4, seq # 1788 mem # 0: /oradata/lipi/redo04.log
  Currently Journal # 4, seq # 1788 mem # 1: /oradata/lipi/redo04a.log
  
  so my point is, we should increase the redo log size to set the checkpoint ends not message, if yes, then what should be the optimum size of the redo log file?
  
  Piyush

  The REDO LOG file must contain at least 20 minutes of data, the log file will be every 20 minutes.
  It is the best practice, otherwise he must log frequent switching and increasing the e/s and waiting.

  The optimum size can be obtained
  by querying the column OPTIMAL_LOGFILE_SIZE of the view V$ INSTANCE_RECOVERY.

  Published by: adnanKaysar on March 11, 2010 17:03

• What is the purpose of waiting for redo log files

  Hello
  
  What is the purpose of the log files waiting for redo in the Dr?
  
  What happens if the standby redo log files are created? or else is not created?
  
  Please explain
  
  Thank you

  Re: what is the difference between onlinelog and standbylog

  I mentioned the goal of the eve of the redo log in RD files in above thread.

  Concerning
  Girish Sharma

• Archive logs always smaller in size then redo logs

  I'm on 10.2.0.3.
  
  My recovery logs (3 groups of 2 members each) is 50 M, while my archive logs is mostly between 30 M and 40 M & never reach 50. Journal Apprently switches are too often produce.
  You guys have an idea, what could cause one - and how to fix it?
  
  TIA.
  
  GROUP # THREAD # SEQUENCE # BYTES MEMBERS OF ARC STATUS FIRST_CHANGE # FIRST_TIME
  ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------------
  YES 1 1 25679 52428800 2 INACTIVE 5176999019 5 MARCH 09
  2 1 25678 52428800 2 YES INACTIVE 5176976984 5 MARCH 09
  3 1 25680 52428800 2 NO CURRENT 5177009713 5 MARCH 09
  
  -rw - r - 1 oracle dba 36288512 5 March 10:45 arch1_25635_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 10:45 arch1_25636_669756456.arc
  -rw - r - 1 oracle dba 38668288 5 March 10:45 arch1_25637_669756456.arc
  -rw - r - 1 oracle dba 40915968 5 March 10:45 arch1_25638_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 10:45 arch1_25639_669756456.arc
  -rw - r - 1 oracle dba 44192768 5 March 10:45 arch1_25640_669756456.arc
  -rw - r - 1 oracle dba 46884864 5 March 10:45 arch1_25641_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 10:46 arch1_25642_669756456.arc
  -rw - r - 1 oracle dba 35848192 5 March 10:46 arch1_25643_669756456.arc
  -rw - r - 1 oracle dba 38760448 5 March 10:46 arch1_25644_669756456.arc
  -rw - r - 1 oracle dba 35851264 5 March 10:47 arch1_25645_669756456.arc
  -rw - r - 1 oracle dba 41501696 5 March 10:47 arch1_25646_669756456.arc
  -rw - r - 1 oracle dba 44226560 5 March 10:47 arch1_25647_669756456.arc
  -rw - r - 1 oracle dba 41139200 5 March 10:47 arch1_25648_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 10:47 arch1_25649_669756456.arc
  -rw - r - 1 oracle dba 36099072 5 March 10:47 arch1_25650_669756456.arc
  -rw - r - 1 oracle dba 43916288 5 March 10:47 arch1_25651_669756456.arc
  -rw - r - 1 oracle dba 43497472 5 March 10:47 arch1_25652_669756456.arc
  -rw - r - 1 oracle dba 36912128 5 March 10:47 arch1_25653_669756456.arc
  -rw - r - 1 oracle dba 35848192 5 March 10:53 arch1_25654_669756456.arc
  -rw - r - 1 oracle dba 36176896 5 March 10:56 arch1_25655_669756456.arc
  -rw - r - 1 oracle dba 36613120 arch1_25656_669756456.arc March 5 from 11:00
  -rw - r - 1 oracle dba 36086784 5 March 11:10 arch1_25657_669756456.arc
  -rw - r - 1 oracle dba 35859456 5 March 11:15 arch1_25658_669756456.arc
  -rw - r - 1 oracle dba 39876608 5 March 11:16 arch1_25659_669756456.arc
  -rw - r - 1 oracle dba 37593088 5 March 11:18 arch1_25660_669756456.arc
  -rw - r - 1 oracle dba 37158912 5 March 11:24 arch1_25661_669756456.arc
  -rw - r - 1 oracle dba 38323200 5 March 11:25 arch1_25662_669756456.arc
  -rw - r - 1 oracle dba 36100096 5 March 11:25 arch1_25663_669756456.arc
  -rw - r - 1 oracle dba 35860480 5 March 11:35 arch1_25664_669756456.arc
  -rw - r - 1 oracle dba 35848192 5 March 11:48 arch1_25665_669756456.arc
  -rw - r - 1 oracle dba 36048896 5 March 11:56 arch1_25666_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 12:05 arch1_25667_669756456.arc
  -rw - r - 1 oracle dba 35990528 5 March 12:07 arch1_25668_669756456.arc
  -rw - r - 1 oracle dba 36060160 5 March 12:12 arch1_25669_669756456.arc
  -rw - r - 1 oracle dba 35888128 5 March 12:16 arch1_25670_669756456.arc
  -rw - r - 1 oracle dba 36460544 5 March 12:18 arch1_25671_669756456.arc
  -rw - r - 1 oracle dba 35857408 5 March 12:21 arch1_25672_669756456.arc
  -rw - r - 1 oracle dba 37536768 5 March 12:31 arch1_25673_669756456.arc
  -rw - r - 1 oracle dba 50753536 5 March 12:32 arch1_25674_669756456.arc
  -rw - r - 1 oracle dba 35850240 5 March 12:38 arch1_25675_669756456.arc
  -rw - r - 1 oracle dba 35854336 5 March 12:53 arch1_25676_669756456.arc
  -rw - r - 1 oracle dba 35875840 5 March 12:56 arch1_25677_669756456.arc
  -rw - r - 1 oracle dba 35873792 5 March 13:07 arch1_25678_669756456.arc
  -rw - r - 1 oracle dba 35852288 5 March 13:19 arch1_25679_669756456.arc

  Hi Grex,

  Refer to metalink Doc ID: 388627.1.

  HTH
  Anand

• Redo Log size recommended

  Hello all,.
  
  For a while I myself have wondered what would be the correct redologsize for a database.
  I found the note
  the new 10g feature: REDO LOG SIZING ADVISORY [ID 274264.1]
  
  who says:
  '+ Rule switching newspapers maximum once every fifteen minutes. + »
  
  Well, I came across a DB with about 3 logswitches per minute (OEL 4.6 environment RAC 10 g 2).
  Do you think that this number is WAY over what it should be? What are your redolog sizes?
  
  The note mentioned also using the instance_recovery view v$ to give advice on the size redolog, which takes into account the MTTR.
  
  Thank you.
  ARO
  Pinela.
  
  Published by: Pinela on November 7, 2011 14:42

  Pinela wrote:
  Thank you all for you comments,

  jgarry,
  Yes, it is a good idea. For the moment, no, there are no errors, messages or complaints. In this case, the impact of the size redolog, refers to restore and cloning operations.

  Aman,
  "more than 4-5 swithces an hour - in general is considered correct". Interestingly, it is a good basis.

  Give more context. The DB in questions about 800 GB, redologs with 50 MB in size and is logswitches 3/4 times each minute (as mentioned earlier) and 1,200 users.

  With these new values, do you everything keep or change your mind?
  I would recommend changing the size redolog to 1 or 2 GB.

  500 MB is very small for a database of ~ 800 GB. For about 2-3 GB of the size of redo log file should be a good start. But please note that only affecting the size of the log file again X value cannot solve the problem. Would be also filled too quickly? If IMO as well as to define the size of redo log to about 3 GB file, you should consider the parameter ARCHIVE_LAG_TARGET so a value which you should expect to maintain for the switching log (as already suggested by others). This would let you control the speed of switching rather than being dependent on the size of the log file or database activity.

  HTH
  Aman...

• SIZE OF THE REDO LOG FILE

  
  Hello

  I got an error message when I add me new group. log files I searched and found the answer on the form. Ago 4 M minimum size of 11 g R2 log file size.

  My question is why a log file size depends on DB_BLOCK_SIZE? This parameter is set to the component structures of memory that create an instance when a log file is an operating system file that depend on the version of the OS not DB_BLOCK_SIZE.

  Thank you.

  
  SQL > alter database add logfile group 4 'c:\app\asif\oradata\employee\redo04.log' size 1 m;
  alter database add logfile group 4 'c:\app\asif\oradata\employee\redo04.log' size 1 m
  *
  ERROR on line 1:
  ORA-00336: 2048 blocks the size of the log file is minimum lower than 8192 blocks

  
  SQL > show parameter db_block_size

  VALUE OF TYPE NAME
  ------------------------------------ ----------- ------------------------------
  Whole DB_BLOCK_SIZE 8192
  SQL >

  You are assuming that the redo log block size is the same as the database block size. This is not correct.

  The error indicates that 8192 is the minimum number of blocks of a redo log file. The documentation states that the minimum size is 4 M. For example, you can deduct your redo log block size is 512 bytes.

  Here's some more information about the size of redo log, the documentation block.

  Unlike the database block size, which can always be between 2 K and 32 K, redo log default files to a block size that is equal to the size of physical sector of the disk. Historically, it is usually 512 bytes (512 b).

  Some new large disks offer 4K sizes byte (4K) to increase sector efficiency improved format and ECC capabilities. Most of the Oracle database platforms are able to detect this bigger sector size. The database then automatically creates files redo log with a block size of 4 K of these discs.

• What are the causes of archivedlog of size to be different from the size of the online redo log?

  11 GR 2 on RHEL 6.2

  4 GB is our size of Redo Log online.

  SQL > select bytes/1024/1024/1024 GB of log v$.

  GB

  ----------

  4

  4

  4

  4

  But the archive logs are 3.55 GB in size instead of 4 GB. Some of the archivelogs that are smaller than 3.55 below must be caused by

  Archive log backup RMAN offers jobs at 10:00, 16:00 and 22:00 that initiates log switching (I guess)

  SQL > select (blocks * block_size/1024/1024/1024) GB of v$ archived_log where status = 'A ';

  GB

  ----------

  3.55978966

  3.31046581

  3.55826092

  3.55963707

  1.39474106

  3.561553

  3.55736685

  3.55881786

  .135155678

  3.55546999

  .054887295

  1.88027525

  .078295708

  1.97425985

  3.55703735

  3.55765438

  .421986103

  3.55839968

  < snipped >

  It has something to do with the parameter FAST_START_MTTR_TARGET ? It is set to zero in this PB anyway.

  SQL > show parameter mtt

  VALUE OF TYPE NAME

  ------------------------------------ ----------- ------------------------------

  fast_start_mttr_target integer 0

  SQL >

  He could carry on public discussions and private discussions as Jonathan Lewis points out in the other discussion that Mihael provides a link to.

  It could concern the parameter archive_lag_target

  It could be the result of the BACKUP of RMAN commands

  It may be a programmed script / who commands ALTER SYSTEM ARCHIVE LOG of employment issues.

  Oracle can create an archivelog that is smaller than the redo log, if it isn't a switch or command before archive the redo log is full.

  Hemant K Collette

• ORA-16038, ORA-00354, ORA-00312 block header corrupt redo log

  Hi all
  
  I'm Ann. I'm not an Oracle DBA. Please bear with me. However, I have to accelerate to become a DBA during the time that the dedicated DBA is on maternity leave.
  As usual, we have the online site and test site.
  She gave me some notes about how to take care of the database of active and application (Oracle 10 g).
  But so far, I can't do a lot of command calls the site online because we have plenty of space for the server, also the biggest part of the task has been scripted. So, it can work automatically.
  
  However, the test database is not like that. There is not automatically restart scripts as in the live system.
  Recently I canont access to the test database. So I connect to the test server, find the folder that contains the Archive Log files is nearly 98%.
  So I remove some of the old dbf files (I did based on the Advisor to the Chief of this last time, it happened a long time ago)
  
  After clear some old files, make a df h the rate at 58%.
  However, the database is still not available (can't open I think)
  I connect to the database, making an immediate halt, but Hung Server.
  So, I ask a network engineer to restart the database server.
  Of course, the machine is stop so the database must be completed.
  After the machine restarts, I connect as sysdba but still cannot open the database.
  The error is as below
  
  
  
  Mounted database
  ORA-16038: log 1 sequence # 1013 cannot be archived
  ORA-00354: corrupted redo log block header
  ORA-00312: thread 1 1 online journal:
  *'/Data/oradata/barn/onlinelog/o1_mf_1_2658nhd4_.log'*
  ORA-00312: thread 1 1 online journal:
  *'/arclogs/oradata/BARNTEST/onlinelog/o1_mf_1_2658nhd4_.log'*
  
  I search and I get these
  ORA-16038, ORA-00354, ORA-00312 block header corrupt redo log
  
  + (http://arjudba.blogspot.co.nz/2008/05/ora-16038ora-00354ora-00312-corrupt.html) +.
  Error description:
  ------------------------
  Normal users could not connect to the database. He messaged ORA-00257: internal connection only up to this just released. When you try to archive the redo log, it returns the message.
  
  ORA-16038: log %s sequence # %s cannot be archived
  ORA-00354: corrupted redo log block header
  ORA-00312: ' %s % s: "%s '" thread online journal
  
  
  Explanation of the problem:
  -------------------------------
  Whenever the normal user tried to connect to the database returns the error as it is designed in
  
  ORA-00257. But you've noticed that there is enough space in the V$ RECOVERY_FILE_DEST. Whenever you look at alerts log, you will see the ORA-16038, ORA-00354, error ORA-00312 serial. Produced error as because it doesn't have archives online redolog due to an alteration in the online redo file.
  
  Solution of the problem:
  --------------------------------
  Step 1) while making your database running clearly non archived redo log.
  SQL > alter the clear database untarred logfile "logilename";
  
  What makes corruption disappear which causes the contents of the redo online deleted file.
  Step 2) make a full backup of the database
  
  Is my question here safe to apply the following steps:
  We have 2 logs online that cause the error, until I need to erase the 2 files.
  
  For step 2, how to make a backup with RMAN.
  Can you suggest a command line safe for me to use. (The EM console surrently do not work on the test database server)
  
  I really need that test database managed as my apps APEX run on this need to be exported to the live system.
  
  Really appreciate any help here, once again, it's an Oracle 10 g release 1.
  
  Kind regards
  
  Published by: Ann586341 on April 30, 2012 15:40
  
  Published by: Ann586341 on April 30, 2012 15:40

  Your problem is with redolog 1

  SQL > select * v log$;

  check the status of the Group 1 regardless of whether ACTIVE or INACTIVE.

  If it is INACTIVE, then run the command below

  SQL > ALTER DATABASE CLEAR NO ARCHIVED LOGFILE GROUP 1;

  then

  SQL > alter database open

  Published by: Vishwanath on April 30, 2012 10:11

• Question about the size of the redo log buffer

  Hello
  
  I am a student in Oracle and the book I use says that having a bigger than the buffer log by default, the size is a bad idea.
  
  It sets out the reasons for this are:
  
  >
  The problem is that when a statement COMMIT is issued, part of the batch validation means to write the contents of the buffer log for redo log to disk files. This entry occurs in real time, and if it is in progress, the session that issued the VALIDATION will be suspended.
  >
  
  I understand that if the redo log buffer is too large, memory is lost and in some cases could result in disk i/o.
  
  What I'm not clear on is, the book makes it sound as if a log buffer would cause additional or IO work. I would have thought that the amount of work or IO would be substantially the same (if not identical) because writing the buffer log for redo log files is based on the postings show and not the size of the buffer itself (or its satiety).
  
  Description of the book is misleading, or did I miss something important to have a larger than necessary log buffer?
  
  Thank you for your help,
  
  John.
  
  Published by: 440bx - 11 GR 2 on August 1st, 2010 09:05 - edited for formatting of the citation

  A commit evacuates everything that in the buffer redolog for redo log files.
  A redo log buffer contains the modified data.
  But this is not just commit who empty the redolog buffer to restore the log files.
  LGWR active every time that:
  (1) a validation occurs
  (2) when the redo log is 1/3 full
  (3) every 3 seconds
  It is not always necessary that this redolog file will contain validated data.
  If there is no commit after 3 seconds, redologfile would be bound to contain uncommitted data.

  Best,
  Wissem

• Files redo log by using the optimal_logfile_size to design view.

  Concerning
  
  I have a specific question about the size of the log file. I have deployed a database of test and I was exploring some aspects regarding the selection of the optimal size of recovery for performance logs by using the view v$ instance_recovery optimal_logfile_size. My main goal is necessary for example to reduce the bytes redo recovery. Currently I have not been able to optimize the size of redo log file. Here are the steps I followed: -.
  
  In order to use the view v$ instance_recovery, I had to put the fast_start_mttr_target parameter which is by default do not then I did as follows: -.
  
  (1) SQL > sho parameter fast_start_mttr_target;
  
  VALUE OF TYPE NAME
  ------------------------------------ --------------------------------- ------------------------------
  fast_start_mttr_target integer 0
  
  (2) setting the fast_start_mttr_target requires destroy deferred to the following parameters: -.
  SQL > show parameter log_checkpoint;
  
  VALUE OF TYPE NAME
  ------------------------------------ --------------------------------- ------------------------------
  log_checkpoint_interval integer 0
  log_checkpoint_timeout around 1800
  log_checkpoints_to_alert boolean FALSE
  
  SQL > select ISSES_MODIFIABLE, ISSYS_MODIFIABLE, ISINSTANCE_MODIFIABLE, ISMODIFIED parameter of $ v where name like 'log_checkpoint_timeout;
  
  ISSES_MODIFIABL ISSYS_MODIFIABLE ISINSTANCE_MODI ISMODIFIED
  --------------- --------------------------- --------------- ------------------------------
  IMMEDIATE FALSE TRUE FALSE
  
  SQL > alter system set log_checkpoint_timeout = 0 scope = both;
  
  Modified system.
  
  SQL > show parameter log_checkpoint_timeout;
  
  VALUE OF TYPE NAME
  ------------------------------------ --------------------------------- ------------------------------
  log_checkpoint_timeout integer 0
  
  (3) setting fast_start_mttr_target now
  
  SQL > select ISSES_MODIFIABLE, ISSYS_MODIFIABLE, ISINSTANCE_MODIFIABLE, ISMODIFIED parameter of $ v where name like 'fast_start_mttr_target;
  
  ISSES_MODIFIABL ISSYS_MODIFIABLE ISINSTANCE_MODI ISMODIFIED
  --------------- --------------------------- --------------- ------------------------------
  IMMEDIATE FALSE TRUE FALSE
  
  Definition of the fast_mttr_target to 1200 = 20 minutes of the control point of switching on the recommendation of the Oracle
  
  Ask the view v instance_recovery $
  
  (4) SQL > select ACTUAL_REDO_BLKS, TARGET_REDO_BLKS, TARGET_MTTR, ESTIMATED_MTTR, OPTIMAL_LOGFILE_SIZE, CKPT_BLOCK_WRITES from v$ instance_recovery;
  
  ACTUAL_REDO_BLKS TARGET_REDO_BLKS TARGET_MTTR ESTIMATED_MTTR OPTIMAL_LOGFILE_SIZE CKPT_BLOCK_WRITES
  ---------------- ---------------- ----------- -------------- -------------------- -----------------
  276 165888 * 93 * 59 361 16040
  
  Here target MTTR was 93 so I put the fast_mttr_target to 120
  
  SQL > alter system set fast_start_mttr_target = 120 scope = both;
  
  Modified system.
  
  The size of the log file suggested by v$ instance_recovery is now 290 MB
  
  SQL > select ACTUAL_REDO_BLKS, TARGET_REDO_BLKS, TARGET_MTTR, ESTIMATED_MTTR, OPTIMAL_LOGFILE_SIZE, CKPT_BLOCK_WRITES from v$ instance_recovery;
  
  ACTUAL_REDO_BLKS TARGET_REDO_BLKS TARGET_MTTR ESTIMATED_MTTR OPTIMAL_LOGFILE_SIZE CKPT_BLOCK_WRITES
  ---------------- ---------------- ----------- -------------- -------------------- -----------------
  59 165888 93 59 290 16080
  
  After you change the size of the logfile to 290 as indicated below by v$ log view;
  
  SQL > select GROUP #, THREAD #, SEQUENCE #, BYTES of the log v$.
  
  GROUP # THREAD # SEQUENCE # BYTES
  ---------- ---------- ---------- ----------
  1 1 24 304087040
  2 1 0 304087040
  3 1 0 304087040
  4 1 0 304087040
  (5) after you change the size, I observed the anomaly as redo log blocks to be applied for the recovery went to * $ 59 to 696 * v instance_recovery view is now also now offers the size of the log file of * 276 MB *. Have I misunderstood something
  
  SQL > select ACTUAL_REDO_BLKS, TARGET_REDO_BLKS, TARGET_MTTR, ESTIMATED_MTTR, OPTIMAL_LOGFILE_SIZE, CKPT_BLOCK_WRITES from v$ instance_recovery;
  
  ACTUAL_REDO_BLKS TARGET_REDO_BLKS TARGET_MTTR ESTIMATED_MTTR OPTIMAL_LOGFILE_SIZE CKPT_BLOCK_WRITES
  ---------------- ---------------- ----------- -------------- -------------------- -----------------
  * 696 * 646947 120 59 * 276 * 18474
  
  If please specify the output above, that I'm unable to optimize the size of the log file and have not been able to achieve the goal of reducing the redo log blocks to apply for recovery, any help is appreciated in this regard.

  I don't think that test for the optimum size of redo's CTD. Maybe if you did each week, as a regular or something, but the unique initial setup and sometimes check in production? N ° but it will be iterative as part of a deployment of init.ora Exchange.

  In addition, it is part of the DBA job to understand the recovery and what to expect. Which includes the understanding of all these parameters, init and tests for the environment. It also includes an understanding of the characteristics of the application and its load.