How RMAN do online backup?

When doing RMAN online backup, all datafiles are not in backup mode( not like user managed backup). How oracle did that? multifiles backup at same time without redo and undo.
Thanks.

From Article Note:76736.1 RMAN FAQ: Recovery Manager -- Frequently Asked
To understand why RMAN does not require extra logging or backup mode,
you must first understand why those features are required for non-RMAN
online backups.
A non-RMAN online backup consists of a non-Oracle tool, such as cp or
dd, backing up a datafile at the same time that DBWR is updating the
file. We can't prevent the tool from reading a particular block at the
exact same time that DBWR is updating that block. When that happens,
the non-Oracle tool might read a block in a half-updated state, so that
the block which is copied to the backup media might only have been
updated in its first half, while the second half contains older data.
This is called a "fractured block". If this backup needs to be restored
later, and that block needs to be recovered, recovery will fail because
that block is not usable.
The 'alter tablespace begin backup' command is our solution for the
fractured block problem. When a tablespace is in backup mode, and a
change is made to a data block, instead of logging just the changed
bytes to the redo log, we also log a copy of the entire block image
before the change, so that we can reconstruct this block if media
recovery finds that this block was fractured. That block image logging
is what causes extra redo to be generated while files are in backup
mode.
The reason that RMAN does not require extra logging is that it
guarantees that it will never back up a fractured block. We can make
that guarantee because we know the format of Oracle data blocks, and we
verify that each block that we read is complete before we copy it to the
backup. If we read a fractured block, we read the block again to obtain
a complete block before backing it up. non-Oracle tools are not able to
do the same thing because they do not know how to verify the contents of
an Oracle data block.
Backup mode has another effect, which is to 'freeze' the checkpoint in
the header of the file until the file is removed from backup mode.
We do this because we cannot guarantee that the third-party backup
tool will copy the file header prior to copying the data blocks.
RMAN does not need to freeze the file header checkpoint because we
know the order in which we will read the blocks, which enables us to
capture a known good checkpoint for the file.

Similar Messages

RMAN vs Online backup

what would be the main advantages to use RMAN vs Online backup?
On both backup/recovery stand point, RMAN is a lot more reliable and less user error/easy to recover/ faster backup and revocery time?
I am using online backup but want to switch to RMAN..

RMAN is the oracle suggested way of doing backups. RMAN automates a lot of the things that you need to handle if doing a backup the "old fashioned way". Things like the spfile, etc are automatically done w/ the backup.
Another advantage is that RMAN only backs up blocks that are used, so if you have a datafile that is 2G, but only 100M of it is used it will only have to backup 100M, where with a manual backup you would need to backup the entire file.
Is one way better than another? It is hard for me to say, once you become familiar with RMAN, you'll wonder why you didn't learn it earlier.
My 2 cents anyway.

How to use online backup services with a Mac.

I want to use an online backup service but each one I check out is unable to backup at least one of my key files and perhaps others that I havent tested yet.
I use an old palm pda and a current version of the palm desktop for mac. I'm quite happy with it and have tons of info on it.
But the online backup services store the files on an IBM server and when I restore it to my Macbook I get a Unix. exe file that I cannot use. I cant even import it or open it on a pc (which would be an acceptable solution in case of an emergency).
I really need a good backup solution for all my Mac files.
I've spoke to Apple, Palm and the techs at the online backup services and no one has a solution.
Any ideas would be appreciated.

You are very welcome. I don't think you can do scheduled updates. Apparently what happens is that the update happens whenever anything is changed on the desktop iDisk. No you don't have to recreate the desktop iDisk ever. That is, you can leave it on your desktop continuously. I trashed mine because I don't like to have things working in the background if I don't currently need them. On the other hand if I changed many things in a day, then I'd leave it on the desktop continuously.
If you check out all the MobileMe features, then you might decide that you like it. Your Dock mail program mirrors exactly what is on the MobileMe online mail program. I have to admit that the online program is very slow. But, the on Dock program more than makes up for the deficiency. Back to Mac is a cool feature. And, the online photo album feature is very easy and works well, except that it doesn't seem able to handle animated gifs.
Message was edited by: donv (The Ghost)

AIR Sqlite can support online backup from memory to disk??

like this link:
http://www.sqlite.org/backup.html
how can i online backup my Sqlite dataBase from memory to disk?

You will need to remove the internal storage from that 2010-11 MBA, and put it in an external USB3 enclosure for use with a 2014 MBA. The assumption here is that the logic board failure did not corrupt the internal storage contents.

Bd2 online backup

Hello experts,
we are using bd2 on linux.
we use following command line to take offline backup:
brdb6brt -bm BACKUP -bpt '/dev/st0' -nb 3.
how to take online backup.
can any one help me out with the command line used for online backup.
we are using HP ALTRUIM tape drives.
thanks and regards,
pratap

Hi Pratap,
To run an online backup, you can use the db2 CLP command, db2 BACKUP DATABASE.. For example,
db2 backup database <sid> online to /dev/st0 -nb 3
You can refer to the IBM Info Center:
[http://publib.boulder.ibm.com/infocenter/db2luw/v9/topic/com.ibm.db2.udb.admin.doc/doc/r0001933.htm]
Also, you can schedule the online backup in DBA Planning Calendar (transaction db13). With this transaction, you can specify when the backup will run in a recurring manner.
I hope it helps!
Regards,

How does recovery work after an online backup

Hello,
While trying to conceptually understand how backup and recovery works, I came accross a question concerning hot (online) backup.
This is a conceptual question (I am trying to understand how things work), it is not a "how should I proceed/ what should I do step by step" question.
As far as I understand, an online backup of a tablespace can be performed by copying the OS files making up a tablespace while the database is up and being used (i.e. transactions are modifying data in the database). Before the copying of the OS files starts, the Oracle RDMS must be notified that an online backup is being taken via "ALTER...BEGIN BACKUP" (such that some additional information is written to the Redo Log, which may be required for subsequent recovery using the online backup). During recovery the Oracle RDBMS uses the copies of the OS files together with the online and archived redo logs in order to reconstruct all committed transactions and it further uses the UNDO tablespace to rollback open (uncommitted) transactions.
Thinking about this, it seems to me, that in order for this to work in all possible scenarios the undo information from the time the backup was taken may be required. Therefore backup of the UNDO tablespace should be taken as well (see the explanation for this assumption below). However browsing the internet (including the Oracle online documentation) I did not find any statements concerning the backup of the UNDO tablespace when an online backup is taken. Moreover I couldn't figure out when exactly such a backup of the UNDO tablespace must be done, to ensure that the database can be recovered in all scenarios.
I believe that undo information from the time the hot backup was taken may be required e.g. in the following scenario:
Assume we are taking a hot backup of a given tablespace, i.e. we are copying all OS files that make up this tablespace, while the database is potentially being used. Let D1 be one of the datafiles in our tablespace and let transaction T1 modify datafile D1. Let transaction T1 further be uncommitted while the copy of datafile D1 is being made and let (at least some of) the changes from T1 be included in the backup copy D1' of D1 (because DBWR has already written the modified blocks at the time they were being copied to the backup). Let transaction T1 be rolled back after the copy is completed. D1' will thus contain modifications from T1, while D1 will not.
Now some time later the datafile D1 is lost. When recovering D1 from the copy D1', the (archived) redo logs will be applied to D1'. Before that, transaction T1 should be rolled back in the copy D1', because modifications from T1 must not appear in the recovered version of the database.
I do however not understand, where the information to rollback transaction T1 exactly comes from. It may still be in the current UNDO tablespace. I do however assume that rollback information is not kept in the UNDO tablespace forever. I see three possible answers to this
(a) There are some requirements which I missed so far to backup the UNDO tablespace whenever a hot backup is made.
(b) Since the Oracle "RDBMS" has to be notified that an online backup is being done, it might store all relevant undo information (e.g. write it to the redo log) when the tablespace is put in backup mode.
(c) There are situations when recovery is not possible due to "missing old UNDO information".
Answer (b) seems the most plausible to me. I did however not find any confirmation of this and if (b) really is the answer, I would be interested to understand what information is stored where by the Oracle RDMBS and how it is used for recovery.
To summarize I have the following questions:
(I) Is there any requirement to backup the UNDO tablespace together with an online backup of a tablespace, and if so, where is this stated in the Oracle documentation?
(II) What mechanisms ensure that uncommitted transactions can be cleared from the online copy of a tablespace (potentially a long time after the copy was taken)?
(III) Do you know any links (Oracle documentation or other online resources) explaining these datails?
Thank you for any hints and answers
kind regards
Martin

Its a highly technical question and I can be completely wrong due to my very less knowledge but I would attempt to answer still. Hope I say something sensible so bear with me.
As far as I understand, an online backup of a tablespace can be performed by copying the OS files making up a tablespace while the database is up and being used (i.e. transactions are modifying data in the database).Correct. But it would depend on the tool you are going to use to do so.Using o/s level commands like CP and all would require you to manually copy the files to the backup location. Using RMAN, it would be lot easier and RMAN would take care of everything.
Before the copying of the OS files starts, the Oracle RDMS must be notified that an online backup is being taken via "ALTER...BEGIN BACKUP" (such that some additional information is written to the Redo Log, which may be required for subsequent recovery using the online backup). Again, this is a requirement only in the case of user-managed backup . In that case, because of the fractured block issue , its important that the corresponding older information/image of the buffer is also copied in the redo stream and that's done when the begin backup command is used. Using RMAN, this is not needed as RMAN can read the consistent image which it would store in the backup piece, exactly in the same way in which select request is fulfilled by oracle for a dirty buffer which is yet to be made consistent.
During recovery the Oracle RDBMS uses the copies of the OS files together with the online and archived redo logs in order to reconstruct all committed transactions and it further uses the UNDO tablespace to rollback open (uncommitted) transactions.Correct!
Thinking about this, it seems to me, that in order for this to work in all possible scenarios the undo information from the time the backup was >taken may be required. Therefore backup of the UNDO tablespace should be taken as well (see the explanation for this assumption below). >However browsing the internet (including the Oracle online documentation) I did not find any statements concerning the backup of the UNDO >tablespace when an online backup is taken. Moreover I couldn't figure out when exactly such a backup of the UNDO tablespace must be done, to >ensure that the database can be recovered in all scenarios.The reason that its not a must to do so is that if the transaction is yet active, there is no way that Oracle would overwrite the Undo information of it, even if you may come after 100 years, it would be there. The Undo segment would mark those blocks as active undo blockswhich contains the information of that transaction whose status within the transacton table of that undo segment is still marked as active. So its there all the time in the undo tablespace. Now, for an instance, let's assume that the undo is not there as well( it would be but let's assume), the changes made to the undo segment's blocks are also recored in the redo as its just a change happening to any other segment like EMP,DEPT except with the difference that its not done by you but by oracle. So using that information, in the future , if there would be a need to replay those changes, necessary information to do so can be brought up from the redo blocks stored in the redo/archive logs. Yes, if there would be pending transactions that would require Undo information to get them rolled back and you have lost Undo tablespace and have no backup of it , you wont be able to bring back the database as it would be inconsistent and oracle would not let you to do it. In that case, you may require to use hacks to get it up and that would be really tricky situation.
(I) Is there any requirement to backup the UNDO tablespace together with an online backup of a tablespace, and if so, where is this stated in the Oracle documentation?As I said above, it must be there if you are anticipating loss of Undo tablespace. If you have lost it, you would need a backup and all the archive logs and redo logs to recover and get it back to the point where the current database is . Rest, oracle would take care as it would reapply the redo contents of the undo segments over the undo segment and get it consitent.
(II) What mechanisms ensure that uncommitted transactions can be cleared from the online copy of a tablespace (potentially a long time after the copy was taken)?As I said , pending transaction's undo is never overwritten by Oracle. Its always kept and marked as active undo . Only a transaction end would make it elgible to get overwritten and that too won't happen immediately(undo_retention would kick in) .
(III) Do you know any links (Oracle documentation or other online resources) explaining these datails?I have to see if its there some where step by step mentioned and I shall update the reply once I shall find the link. Hoep someone else in the meantime finds it .
HTH
Aman....

Less redo generates at the time of online backup using RMAN

Hi,
can someone eleborate that why less redo generates at the time of RMAN online backup in comparison of manual hotbackup.
Thanks

A manual hot backup (aka "OS backup" or "scripted backup") cannot handle fractured blocks. This happens when a backup command is copying out blocks from a datafile at the same time as DBWR is updating blocks. The Oracle Block Size (8KB) is generally a multiple of the OS Block size (512Bytes to 4KB or 8KB, depending on the filesystem / raw device and how the OS command copies blocks out). It is possible for DBWR to write 8KB and the OS backup utility to be concurrently reading the same Oracle block as, say, two different 4KB reads. The first half of the Oracle block may be read by one OS call and the second half by another OS call -- the two halves would be inconsistent with each other if Oracle were writing the database block at the same time.
(Therefore a restore of such a backup would give you an inconsistent -- i.e. fractured -- block, which would be logically corrupt).
In order to handle such issues, after a BEGING BACKUP is issued, for every first change to a database block, the whole block is written to the redo stream, not just the change vectors. (If the same database block is subsequently modified while in BACKUP mode, it is only the change vectors that have to be written to the redo stream). Once the END BACKUP is issued, the redo stream does not need to capture whole database blocks.
If such a backup is restored, it still has fractured blocks. However, when applying the ArchiveLogs generated during the Backup, each such fractured block is "automagically repaired" because a whole image is restored from the ArchiveLog. (Subsequent changes are replayed as changes through the change vectors).
Hemant K Chitale
http://hemantoracledba.blogspot.com

Online Backups Rman

HI,
I have setup an oracle database running one of our inhouse applications on a Linux Red Hat 4 Enterprise OS. Project go live
is a few days away and I don't have time to teach myself Oracle backups at this stage. I was hoping a few experts could
help me out with the following.
1. What configuration settings do I make to Oracle database and RMAN to prepare for online backups? How do I check
that the settings have already been done?
2. what commands do I then run to trigger off a online backup and what script type do you use so it can be scheduled?
3. How do you schedule the online backup?
My plan its to do an online backup to a folder on another partiton and then use rsync to sync the backup over to another
server which has tape backup.
I also though of running a script to shutdown the databse, then use rsync to copy the databse to a new location and then
startup the database again. Anyone ever use this backup type?
Many Thanks!
Raikal.

Hi 581156,
You can use RMAN to do your online backups, please can you tell us your RDBMS version,OS and if the DB is on archive mode or not? I need this to send you the right links to help you on this process.
Please take a look on this link:
http://www.orafaq.com/wiki/Oracle_database_Backup_and_Recovery_FAQ
Also if you need more information, please refer to:
http://tahiti.oracle.com/
Cheers,
Francisco Munoz Alvarez

Ebs r12 cloning using rman online backup

dear all,
how are you guys? i have ebs r12 on multi node and i want to clone db tier and apps tier using rman online backup,can anybody provide me the detail steps of cloning ebs(db tier and appstier ) using rman online backup and directory structure on source and target database is also different.your help highly appreciated thanks in advance.
regards.

Hi,
You cannot use RMAN to clone the Apps tier of the EBS and you may use RMAN only on the DB tier. For a complete backup, as mentioned by Hemant K Chitale, you will have to use the rapid clone utility.
To perform a rapid clone using RMAN there are plenty of step by step instructions in google which may guide in addition to support.oracle.com, Let me google that for you
Thanks &
Best Regards,

How do i get rid of the charge on my debit card for online backup?

how do i get rid of the charge on my debit card for toshiba online backup? Backup has not been functional for months. I called the customer service number and eventually was transfered to some apartment complex phone number.

Hi there!
You cal to customer services of your bank or credit card and being told as disenroll in Argentina is usually effective.
Another way is Toshiba customer that you want to cancel the service, it is your right.
Because you have hired an online backup service with so many free payment? On the other side is always better physical backup, at least I think so.
Best regards.

Online backup and RMAN

Can I do online backup / RMAN together?
I want to shedule both online back up and RMAN running on everyday..
Is there any known issue by doing this?

Hi,
Yes you can do but what is need to use two method for backup.
is there anything special reason.
regards
Taj

HT4759 500GB online backup how to put it on

I purchased the 500GB online backup in store but don't know how to put it on can someone help me please.

What are you talking about?

How to restore specific backup file from RMAN?

Hi,
I am just begginer with Oracle DB so I do not have a lot knowledge.
I created two backups at April the 8th and April the 10th.
I did following from RMAN.
shutdown immediate
startup mount
configure channel 1 device type disk format '/opt/oracle/backup/std_%U';
backup database
startup
output was:
including current control file in backupset
including current SPFILE in backupset
it created two files: std-0so6l0vn(2 GB) and std_0to6l106 (7 MB).
First question - first file is backup and what is the second file???
Today I created also backup and it also created two files: std_0uo6morg (2GB) and std_0vo6morv (7MB)
Now I want to return backup from 2 days ago (*std-0so6l0vn*) but can't;
I do the the following:
shutdown immediate
startup mount
restore database from '/opt/oracle/backup/std_0so6l0vn'
but getting error - only SPFILE or control file can be restored from autobackup.
How to restore my backup from two days ago? It looks to me so complicated and hardly understandable.
What command to execute from RMAN to succeed in restore?
Thank you

I still can not restore database; I tried Honza method.
i try
startup nomount
restore controlfile from 'restore controlfile from /opt/oracle/backup/sss_11o7efd9_1_1';
And getting message:
no autobackup found or specified handle is not a valid copy or piece
list backup returns:
BS Key Type LV Size Device Type Elapsed Time Completion Time
19 Full 6.80M DISK 00:00:01 19-APR-13
BP Key: 19 Status: AVAILABLE Compressed: NO Tag: TAG20130419T025522
Piece Name: /opt/oracle/backup/sss_11o7efd9_1_1
Control File Included: Ckp SCN: 3178467 Ckp time: 19-APR-13
SPFILE Included: Modification time: 02-APR-13
show all returns:
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
configuration for DISK channel 2 is ignored
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL 1 DEVICE TYPE DISK FORMAT '/opt/oracle/backup/sss_%U';
CONFIGURE CHANNEL 2 DEVICE TYPE DISK FORMAT '/opt/oracle/backup/sss_%U';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/opt/oracle/product/10.2.0/dbs/snapcf_ctginst1.f'; # default
Please help I really must restore database but can't do it.

No Online backups due to datafiles offline than I canu0092t recover. How...?

Hi gurus!!!
I got into a problem with some datafiles.
We have MySAP in a BD oracle 9.2.0.6
I used Oracle Entreprise Manager Console to generate two datafiles in the tablespace PSAPPRDUSR,
but I generated them in another tablesapce (PSAPPRD) with a name of file,
size and location very different from those that there uses the tablespace PSAPPRD.
So... I put them offline later to erase them later!!!
The datafiles contains no data.
Later, in the night backup:
 BR0334W Status of database file /oracle/PRD/sapdata4/prdusr_2/prdusr.data2 is RECOVER
 BR0334W Status of database file /oracle/PRD/sapdata4/prdusr_2/prdusr.data2a is RECOVER
 BR0301E SQL error -1128 at location BrTspAlter-3
 ORA-01128: cannot start online backup - file 31 is offline
 ORA-01110: data file 31: '/oracle/PRD/sapdata4/prdusr_2/prdusr.data2'
 BR0280I BRBACKUP time stamp: 2007-04-20 03.01.21
 BR0316E 'Alter tablespace PSAPPRD begin backup' failed
 BR0056I End of database backup: bdvbtndh.ant 2007-04-20 03.01.21

And now... I neither can erase them nor can put online again.
To erase them I used:
SQL> ALTER DATABASE DATAFILE '/oracle/PRD/sapdata4/prdusr_2/prdusr.data2' OFFLINE DROP;
Database altered.
SQL> commit;
But they continue there, do not resign.
To put them online:
SQL> alter database recover datafile '/oracle/PRD/sapdata4/prdusr_2/prdusr.data2';
alter database recover datafile '/oracle/PRD/sapdata4/prdusr_2/prdusr.data2'
ERROR at line 1:
ORA-00279: change 31203204 generated at 04/19/2007 19:30:11 needed for thread 1
ORA-00289: suggestion : /oracle/PRD/oraarch/PRDarch1_2574.dbf
ORA-00280: change 31203204 for thread 1 is in sequence #2574
SQL>
But we have continued working and I don't want to lose any data.
HEEEELP!!!!
What I can do to recover the datafiles and to continue with my daily Online backups?
The BD is in production and I do not have long time to fix it, only a few hours on Saturdays night.

Hi,
alter database datafile offline drop;
This command is not meant to drop a datafile. It is meant to offline the datafile with the intention of dropping the tablespace.
For a tablespace comprising multiple datafiles you can only drop a datafile by dropping the entire tablespace, this will work even you have one datafile.
If you have 10gr2, it's finally possible to drop a datafile as long as
it's not the only datafile within the tablespace, and
the tablespace is only and in read-write status.
So since you are on 9i your situation in summary:
If you have more than one datafile in the tablespace and you wish to keep the objects that reside in the other datafile(s) which are part of this tablespace, then you must export all the objects inside the tablespace.
1. Gather information on the current datafiles within the tablespace by running some query to remember the t/s, segment, and datafile info.
2. Export all the objects that you wish to keep.
3. Once the export is done, issue the DROP TABLESPACE <tablespace name> INCLUDING CONTENTS.
4. Delete the datafiles belonging to this tablespace using the operating system.
5. Recreate the tablespace with the datafile(s) desired, then import the objects into that tablespace.
Hope this helps and good luck,
George

Aperture vs Carbonite online backup

Welcome,
I'm wondering if actualy any of you use Carbonite online backup services. For flat 50$ yearly fee they offer unlimited online storage and a backup program.
My current backup scheme includes Time Capsule plus Vault for Aperture, that is updated from time to time. I do like the idea of offsite storage of my data, and when I say data I'm mainly concerned with my photos.
I don't expect Carbonite software to be Aperture library aware, and my library is not very big but it grows (46GB today plus 30GB iPhoto waiting for better times to be migrated into Aperture) - and this. I don't use referenced files and now I'm starting thinking about file and backup management scheme, that would eventually include Carbonite.
So here are my concers:
1. I assume, that in order to backup and restore I must have whole library, means in my case almost 80GBs - probably to much to achive reasonable restore time, even if I don't make money of my pictures.
2. What would happen if I move to referenced files? Will I be able to restore library only in limited time, and then let Carbonite restore all my pictures - this may even take days (means RAW, JPEG, PS, sometimes TIFF)? Will the library (previews and thumbs work in the mean time?
3. Does anyone can tell me what size would be a DB that has, lets say, a 150GB of referenced photos (double sieze of my current library?
Any toughs, will such service work for Aperture users?
Thanks in advance for your inputs,
Adam

Hi Eric,
thank you very much for your response.
So it is imposible to implement the back up strategy with incremental back up without applying RMAN, right?
Then I should set up my strategy as follows:
- daily whole database backup
- daily two times redo log backup
How difficult it is to set up RMAN in order to use incremental back up?
Many thank's
Regards
Thom

How RMAN do online backup?

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