Differential VS Cumulative

In comparison of differential and cumulative, cumulative uses more storage space but faster recovery as differential might require more than one level in order for recovery to be completed; where cumulative only required the latest level of backupset? Am I right on this? Backup process of cumulative will take longer time compare to differential?
Other than that, what other pros and cons between this two incremental?
Thanks

Your scripts are following the scenario 1. Incremental backups are by default
differential. Since you are using the keywork CUMULATIVE, it's the 1 scenario.
What made you doubtfull? Scripts are straight forward.......

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RMAN Cumulative and differential level 1taking too much time

hi,
I am attempting to HOT backup my 600 GB database to backup into Tape using NMO 5 EMC Networker 7.6.
My networker server is on Win Serv 2003.
My oracle database is on RHEL 4.5 Architecture ia64
Oracle DB Version 10.2.0.4.0
Using ASM
Using EMC Storage as Databse storage
Using tape backup media type LTO-Ultrium-5
No of chaneels used same for bothLevel 0 & 1 is 4
there are 60 Datafiles fior the database
i am atttempting incremental backup[Hot] backup
for Incrementa Level 0 is taking 90 Minutes to complete.
BUT leve1 backup [Both differential and cumulative] are taking almost the same time as taken for Level 0 backup
almost 80Mins.
but the backup Set size for Level 0 is almost 500 GB and Sizes for any Level 1 backup not more than 200MB.
i am confused if both LEVEL 0 AND LEVEL 1 BACKUP should take the same span of time.
please help to reduce the time to complete the Level 1 backups..
thanks in advance

RMAN incremental level 1 and up will have to verify every block in the data files to identify if any modifications have occurred. The time it takes to complete the incremental backup will depend on how much changed. Are you using the latest patches? There are known bugs that can affect performance problems with RMAN backup and recovery. Otherwise, check the Oracle documentation to troubleshoot RMAN.
Block change tracking as already mantioned, introduced in 10g, can greatly speed up your incremental level 1 and up backups.
From what I understand:
SQL> ALTER DATABASE ENABLE BLOCK CHANGE TRACKING USING FILE '/mydir/rman_change_track.f';
As soon as block change tracking is enabled, Oracle starts to record every block that updates. The information is stored in a bitmap inside the BCT file. Every incremental backup causes a bitmap swtich in the BCT file.
If there exists a previous bitmap beside the current bitmap, then an incremental level 1 backup will only backup the blocks according to the current bitmap. Incremental level 1 backups are differential backups by default. If there is no previous bitmap, the RMAN backup will perform a conventional scan of the database as usual.
The bitmap logic applies also to cumulative level 1 incremental backups, which will use all the bitmaps recorded since the last bitmap switch from a level 0 incremental backup. Due to the limit of 8 bitmaps, a cumulative incremental level 1 backup will have to perform a conventional scan of the database, if you make a level 0 database backup followed by 7 differential incremental backups.

Cumulative Incremental?

Hopefully you all can resolve a question for me. I was under the impression that a CUMULATIVE backup and an INCREMENTAL backup were two separate things.
INCREMENTAL LEVEL : Copies only those data blocks that have changed since the last incremental integer backup, where integer is 0 or 1 (see Example 2-16).
CUMULATIVE : Copies the data blocks used since the most recent level 0 backup (see Example 2-16).
So I go to "Example 2-16"...
http://docs.oracle.com/cd/B28359_01/backup.111/b28273/rcmsynta007.htm
Example 2-16 Performing a Cumulative Incremental Backup
This example backs up all blocks changed in the database since the most recent level 0 incremental backup. If no level 0 backup exists when you run a level 1 backup, then RMAN makes a level 0 backup automatically. Any inaccessible files are skipped.
BACKUP
INCREMENTAL LEVEL 1 CUMULATIVE
SKIP INACCESSIBLE
DATABASE;I am confused. I thought that cumulative/incremental were exclusive backup types. How can they both be referenced in the same code block?
Thanks

Hi,
please donot be confuse In the same document it written
Incremental Backups:
An INCREMENTAL backup at level 0 backs up all data blocks in datafiles being backed up. An incremental backup at level 0 is identical in content to a FULL backup,
but unlike a full backup the level 0 backup is a part of the incremental backup strategy.
A level 1 backup copies only changed blocks. A level 1 incremental backup is either differential or CUMULATIVE.
*If cumulative, RMAN backs up all blocks changed since the most recent level 0 backup.*
*If differential, RMAN backs up blocks updated since the most recent level 0 or level 1 incremental backup.*
HTH :)

Quesion about the Basic concept of RMAN incremental backup

I have a problem in understanding the basic concept of two types RMAN Incremental backup ie. Differential and Cumulative. I just don't understand how cumulative incremental backup consumes more space than Differential backup.
Have a look at the scenario in which Differential backup is used.
1. On Sunday midnight, a LEVEL0 backup is taken.
2. On Monday midnight all the blocks that was changed since Sunday midnight are stored in the backup media (tape or disk)
3. On Tuesday midnight all the blocks that was changed since monday midnight are stored in the backup media.
4. On Wednesday midnight, all the blocks that was changed since tuesday midnight are stored in the backup media.
At this point, in the backup media, you have all the changed blocks from sunday midnight to wednesday midnight eventhough it was stored in a daily basis. If you had taken a cumulative backup at wednesday midnight the backup media would have contained the same changed blocks from sunday midnight(LEVEL0) to wednesday midnight, but all at one go instead of daily basis. I don't understand how cumulative backup consumes more space when the backup media contains the same amount of changed blocks as it were in the case of the Differential backup.

Considering the Scenario you given:
Sunday : Level 0 backup.
Monday : You have taken an incremental backup then there will not be any difference in size of backup set for differential or cumulative as the changes from last Level0 backup are considered.
Tuesday : A cumulative backup (n-1) will have changed blocks since Sunday's Level0 backup but a differential backup(n) will only have changed blocks since Monday. So definitely there will be more space consumed by cumulative backups compared to differentials.
Hope it helps ...
Bhupinder

Restore using RMAN

I had taken backup three time say backup1 after few transaction backup2 and after few transactions backup3 using RMAN. RMAN no catalog
Now we want to recover database using backup1.
provide the steps to recover the database using backup1

Hi,
You said you have taken the Backup. Which type of backup either level 0 or level 1 (incremental backups - differential or cumulative). Next type of backups - either image copies or backups. If backups are taken then we can try out to restore specific files from the backup sets - I am not sure on that.
You have to provide the DB Version. ??
What is the need for going for First Backup only... what is the need ??
Does you know appropriate time , if you use the flashback then we can use that.
- Pavan Kumar N
Oracle 9i/10g - OCP
http://oracleinternals.blogspot.com/

RMAN error during auto backup

Hello,
We have crontab to take archivelog backup at every hour at 10 mins. mon-sat incremental and sunday level 0 backup. Today morning I got following error in the log file. (RAC DB 10.2.0.5, OS=RHL)
RMAN-00571:
===========================================================brRMAN-00569: ===============
ERROR MESSAGE STACK FOLLOWS ===============brRMAN-00571:
===========================================================brRMAN-03002: failure of backup
plus archivelog command at 05/21/2012 05:55:59brRMAN-03014: implicit resync of recovery
catalog failedbrRMAN-06004: ORACLE error from recovery catalog database: ORA-03113:
end-of-file on communication channelbrORACLE error from recovery catalog database:
ORA-03114: not connected to ORACLEbrRMAN-00571:
===========================================================brRMAN-00569: ===============
ERROR MESSAGE STACK FOLLOWS ===============brRMAN-00571:
===========================================================brRMAN-03002: failure of
allocate command at 05/21/2012 05:56:00brRMAN-06004: ORACLE error from recovery catalog
database: ORA-03114: not connected to ORACLElist backup of archivelog all; .. while connecting to rman catalog..following are the few lines from the output.
I found almost related MOS note but unfortunately, I am still unable to understand what actually happened or what is trying to be explain in this particular note. RMAN Backup fails with error ORA-3114 [ID 1264084.1]. One more important question for my concern is that if the command failed for example as in my case. The next time when backup command started to take incremental backups, will it cover or backup those archivelog which were not backed up because of the above error?
List of Archived Logs in backup set 2481637
Thrd Seq     Low SCN    Low Time            Next SCN   Next Time
1    67414   27261392224 21-05-2012 05:10:22 27261405217 21-05-2012 05:55:55
1    67415   27261405217 21-05-2012 05:55:55 27261422601 21-05-2012 06:10:07
2    70049   27261392222 21-05-2012 05:10:20 27261405224 21-05-2012 05:55:57
2    70050   27261405224 21-05-2012 05:55:57 27261422604 21-05-2012 06:10:08Thank you.
Best Regards.

A "BACKUP ARCHIVELOG" is not an "Incremental Backup" (ergo, the question of "differential" or "cumulative" doesn't arise).
It is a Backup of the ArchiveLogs specified in archlogspecifier . Since you have specified "ALL" it will attempt to backup all known archivelogs that have not been deleted. The "DELETE ALL INPUT" will delete the files after they have been successfully backed up. If the backup fails, the DELETE is not executed. Therefore, at the next execution, the same (and newer) ArchiveLogs will get backed up.
Why don't you maintain a log of the RMAN Backup run (either with "SPOOL LOG TO .." in the RMAN script or by redirecting STDOUT and STDERR to a custom log file).
Hemant K Chitale

Level 01 backup from 02 Levels 0 backup

Hi friends
I'm running ora 11gr2 on windows environment and I got a doubt on a specific situation.
I have to locations for my rman bkps, A and B, which point to different devices, one local and the other remote.
Imagine I take a LEVEL 0 backup on day 20 pointing to both locations, A and B.
On day 21, 22 and 23 I take a level 01 backup pointing just to the local destination A.
On day 24 I take another LEVEL 0 backup pointing just to location A again....
Now, I want to take a level 1 backup to location B, just to backup the blocks changed since the backup level 0 taken on day 20, bypassing the blocks already taken on days 21, 22, 23...
Is that possible? To control the levels 01 backup from 02 different destinations?
Tks a lot

Can I, after that, backup level1 pointing to location B, AND INCLUDE again all those blocks that have been taken backup on the previous level1, but saved on other location?My answer to this would be, you would be able to take the level1 backup to location B, but that would not include the blocks that would have been backed up by previous level1 saved on other location.
RMAN takes backup of the database as per the levels you mention irrespective of where you have the backup pieces to be stored.
If you are looking out for such an option, I can suggest you to read this http://docs.oracle.com/cd/B19306_01/backup.102/b14192/bkup004.htm to understand and use differential and cumulative backups.

Incremental Backups are Cumulative Vs Differential??

Dear all,
The followings are Weekly Full Backup and Daily Backup scripts:
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;
allocate channel ch1 type disk format '/u02/db/backup/RMAN/backup_%d_%t_%s_%p_%U.bck';
backup incremental level 0 database plus archivelog delete all input;backup current controlfile;
backup spfile;
release channel ch1;
Daily Backup:
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;
allocate channel ch1 type disk format '/u02/db/BACKUP/RMAN/backup_%d_%t_%s_%p_%U.bck';
backup incremental level 1 cumulative database plus archivelog delete all input;delete noprompt obsolete;
delete noprompt archivelog all backed up 2 times to disk;
backup current controlfile;
backup spfile;
release channel ch1;
I will do the full backup on Sunday and daily backup on Mon to Sat.
Scenario 1:
Incremental Backups are cumulative, I need of sunday full backup and tuesday daily backup to restore the database if crash on wednesday.
Scenario 2:
Incremental Backups are differential, then I need of sunday full backup and all incremental backups until crash.
I am wondering which scenario (1 or 2) is for my scripts that I post on above? Because I have different answer from others.
Best Regards,
Amy

Your scripts are following the scenario 1. Incremental backups are by default
differential. Since you are using the keywork CUMULATIVE, it's the 1 scenario.
What made you doubtfull? Scripts are straight forward.......

Restoring RMAN cumulative and differential backupsets

Hi all,
I have 2 queries regarding restoring and recovering rman backupsets.
1) i have backup policy for sunday level 0, wednesdays cumulative backup and other days of the week differential backup.Now if my database crashes on friday afternoon.What would be my action plans for restoring and recovering the database with brief steps for the same.
2)Suppose i have retention policy for 2.And i have a backupset which has become obsolate as the result.Is it possible to restore and recover this obsolate backupset?
Regards
Vijay

1) i have backup policy for sunday level 0, wednesdays cumulative backup and other days of the week differential backup.Now if my database crashes on friday afternoon.What would be my action plans for restoring and recovering the database with brief steps for the same.
Step 1: start up Internet Explorer or Firefox or Chrome
Step 2: Type http://tahiti.oracle.com in the address bar
Step 3: Navigate to the homepage of the version you refuse to mention
Step 4: Look for the Backup and Recovery Manual
Step 5: Consult the Restore and Recovery scenarios in that doc
2)Suppose i have retention policy for 2.And i have a backupset which has become obsolate as the result.Is it possible to restore and recover this obsolate backupset?
Suppose I hired you as a DBA. My database crashes. You start visiting Oracle Forums immediately instead of restoring and recovering the database.
In fact you don't seem to have a clue on the process as you think you can recover a backupset.
What should I do?
Sybrand Bakker
Senior Oracle DBA

Backup incremental level 0 cumulative database

On RMAN Level 0 backup when I say cumulative like below what the difference that command make;
backup filesperset 1 format '<%d_%s:%t:%p:%f>.df' incremental level 0 cumulative database;Edited by: Sivaprasad S on Sep 1, 2012 12:42 AM
Edited by: Sivaprasad S on Sep 1, 2012 12:44 AM

In a cumulative level 1 backup, RMAN backs up all blocks used since the most recent level 0 incremental backup in either the current or parent incarnation. Cumulative incremental backups reduce the work needed for a restore by ensuring that you only need one incremental backup from any particular level. Cumulative backups require more space and time than differential backups because they duplicate the work done by previous backups at the same level.

EM12c Create non-cumulative incremental (level 1) backups against target DB

Is this not available? It appears that we can only create cumulative RMAN incremental backups through Cloud 12c (this is against an 11gR2 DB). Are non-cumulative incrementals no longer supported?

When scheduling a backup through the wizard, the last step displays the RMAN script the wizard has generated for you. Have you tried clicking the 'Edit RMAN Script' and removing the word "cumulative" from the generated script?
I run backups using scripts stored in the recovery catalog so I don't use the click-through backup wizard, but does it not result in a differential incremental backup if you edit the script?

Cumulative Distribution Functions

Like a fool, I sold my first year statistics textbook and have regretted it ever since. Help a guy out?
It goes like this: I have two random variables, X and Y, for which I know the cumulative distribution functions. I have a third random variable Z, which is just X + Y. Is there a formula calculating the CDF of Z from the CDFs of X and Y?

Your textbook wouldn't have helped you in this case
because there is no such formula... for the generalSorry to contradict you but there is a 'formula' but it is not simple. The text book should have helped.
The Distibution Function (DF) of the sum of two independent random variables is the convolution of the DF's of the two values. So if one differentiates the two CDFs to get the DFs, convolves the result to get the DF of the sum one can then integrate the convolution result to get the CDF of the sum (Wow).
This can be done numerically using several appraches. I have used the Fast Fourier Transform to perform convolution, differentiation and integration but not in this combination. This would be one approach I would consider but it may not be the best.
When I first saw this posted I looked at how one might create the CDF without differentiating the individual CDFs because this step is 'noisy' but I could not find a simple approach. I'm sure there is one but I have not found it.
Using the central limit theorem to obtain an approximation to the PDF is feasable if X and Y have a uni-modal distribution and the variances are similar is size. In the good old days of my using an IBM 360 I used IBM's normal distribution random number generator that just added together 6 samples of a uniform random number generator.

Is level 0 backup equivalent to cumulative L1 backup?

Is level 0 backup equivalent to cumulative L1 backup?

No. A level 0 backup is the starting point for any following incremental backups - cumulative or differential. A level > 0 backup always requires a previous level 0 backup, it doesn't matter whether the incremental backup is cumulative or differential.
Werner

Non-cumulative Values not showing in Inventory Management Queries

Hi:
Has anyone had a problem with the new version and Non-cumulative key figures not showing up in Bex for Inventory Managemet reports? Specifically, they showed and validated back to ECC for our Development and QA boxes but now in our Regression box they are all showing zeros. Our Cumulative values are all showing correctly still within the Regression box. For example, Total Receipts and Total Issues are correctly poplating values but Total Stock is not.
I have checked and validate that the configuration in the Regression box matches or Dev and QA box.

Found the problem. It had to do with the compression variant in the delta process chain. The compression was set to 'no marker update'. Since we only started receiving measureable deltas in or regression box this is where the incorrect setting showed up. Reinitalized and the deltas are working correctly now.

Aggregates on Non-cumulative InfoCubes, stock key figures, stock, stocks,

Hi..Guru's
Please let me know if anybody has created aggregates on Non-Cumulative Cubes or key figure (i.e. 0IC_C03 Inventory Management.)
I am facing the problem of performance related at the time of execution of query in 0IC_C03.( runtime dump )
I have tried lot on to create aggregate by using proposal from query and other options. But its not working or using that aggr by query.
Can somebody tell me about any sample aggr. which they are using on 0ic_c03.
Or any tool to get better performance to execute query of the said cube.
One more clarification req that what is Move the Marker pointer for stock calculation. I have compressed only two inital data loading req. should I compress the all req in cube (Regularly)
If so there would be any option to get req compress automatically after successfully load in data target.
We are using all three data sources 2lis_03_bx,bf & um for the same.
Regards,
Navin

Hi,
Definately the compression has lot of effect on the quey execution time for Inventory cubes <b>than</b> other cumulated cubes.
So Do compression reqularly, once you feel that the deletion of request is not needed any more.
And ,If the query do not has calday characterstic and need only month characterstic ,use Snap shot Info cube(which is mentioned and procedure is given in How to paper) and divert the month wise(and higher granularity on time characterstic ,like quarter & year) queries to this cube.
And, the percentage of improvement in qury execution time in case of aggregates is less for non cumulated cubes when compared to other normal(cumulated) cubes. But still there is improvement in using aggregates.
With rgds,
Anil Kumar Sharma .P
Message was edited by: Anil Kumar Sharma

Differential VS Cumulative

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