Why archivelog mode is mandatory for hot backups.

Why the database should be put in archivelog mode when we take hot backups. What happens actually. Why can't we put in noarchivelog mode and take hot backups?

Suppose you are not using RMAN then you must put your tablespaces in backup mode. Otherwise the backup you can take will be unrecoverable.
In order to recover from a Hot Backup you have to do followings
- Restore your Hot Backup
- Recover the database - here, the archive log files are important
How does Oracle know what has to be recovered from archivelogs?It looks at the SCN.
If you never put your tablespaces in backup mode then SCN would not be frozen and Oracle wouldn't know what has to be recovered.
Talip Hakan Ozturk

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  • Minimum privilege for  hot backup

    which privilege is required to take hot backup i want create user to take hotbackup with minimum privilege .now i take hotbackup with SYS user but this is danger because another department should be take hotbackup.
    best regards

    Allahmorad wrote:
    which privilege is required to take hot backup i want create user to take hotbackup with minimum privilege .now i take hotbackup with SYS user but this is danger because another department should be take hotbackup.
    best regards
    allahmoradalter database,alter system, create session is enough privileges to make vast changes in your database.So there is not such priveleges.(as fortmann suggested).
    I will suggest you to use the rman for hot backup.
    Hope this help :)

  • When to use REUSE/SET, NO-ARCHIVELOGS in create controlfile in HOT BACKUP?

    I am a trainee Oracle DBA and have the following queries. Kindly reply with detailed explanation as I want to get my concepts cleared!
    Q1>> While doing a user managed hot backup, when we are creating a control file(CREATE CONTROLFILE) from trace for recovery when do we use the create control file with the following options:
    *1. REUSE / SET*
    Q2>> In what scenarios do we re-create the control file while recovering datafiles from a hot backup??
    Thanks a tonne!

    Hemant K Chitale wrote:
    1.1 It is not "REUSE/SET". These are two very different clauses.
    REUSE is when you want the CREATE to overwrite the existing controlfile(s). If the controlfile(s) {as named in the instance parameter file, initSID.ora or spfileSID.ora} is/are already present, the CREATE fails unless REUSE is specified.
    SET is when you want to change the database name. Oracle then creates the controlfile(s) with the specified database name and updates the headers of all the datafiles. If you run a CREATE with a database name that is different from that in the datafile headers, the CREATE fails unless you include a SET to specify that the name must be changed. Note that this also means that the name in the instance parameter file must already have been updated.
    1.2 ARCHIVELOG/NOARCHIVELOG is to set the database state. The same is achieved by issuing an "ALTER DATABASE ARCHIVELOG/NOARCHIVELOG" when the database is MOUNTed but not OPEN.
    2. You'd run the CREATE CONTROLFILE if you do not have a binary backup of the controlfile.
    Optionally, you can also use CREATE CONTROLFILE to rename all the datafiles by specifying the new locations of the datafiles -- the datafiles must already be present in the new locations, else the CREATE fails if it doesn't find a datafile that is included in the list of datafiles included in the CREATE statement.
    RMAN is the correct way to run Backups. User Managed Backup scripts are used in cases like Storage-based Snapshots / SnapClones / BCV.
    Hemant K ChitaleThanks that was really helpful..One last question when to use the resetlogs/noresetlogs clause in the create controlfile statement. I have noticed that at times it accepts resetlog while at times it accepts noresetlogs

  • Environment configuration for Hot Backups

    Hi all,
    1. I am trying to create a hot backup tool based on the read-only Environment strategy ([discussed in a previous thread|http://forums.oracle.com/forums/message.jspa?messageID=3674008#3674008] ).
    Now, leaving aside the EnvironmentConfig.setReadOnly(true), I have found quite a few possible other configuration options in the EnvironmentParams class and I'm wondering if there are some that I should be using.
    Here are a couple of examples:
    Would it make sense to configure any of these?
    2. After creating a hot backup I have tried to test its state. Basically, the approach was quite simple:
    - open a read-only env on the backup
    - try to access the databases in the env
    My idea is that if the above 2 ops are succeeding then there is a very good chance that the backup is correct.
    Now, while playing with the above configuration options I have noticed that if I'm setting ENV_RECOVERY to false in this test environment, then any attempt to access the databases within results in a DatabaseNotFoundException.
    Can someone help me understand what is happening? (basically, I cannot make a connection between recovery and access to the DBs in the environment)
    Many thanks in advance,
    PS: I've forgot to mention that I'm running a quite old version: 2.1.30
    Edited by: Alex Popescu on Aug 13, 2009 5:50 AM

    ENV_RECOVERY - suppresses running recovery at Environment creation. Internal parameter.
    ENV_RUN_INCOMPRESSOR, ENV_RUN_CHECKPOINTER, ENV_RUN_CLEANER - disable the INCompressor, Checkpointer, and Cleaner Daemon threads.
    You should not need to adjust any of these parameters for your DbBackup utility. In fact, ENV_RECOVERY is an "internal use only" parameter.
    PS: I've forgot to mention that I'm running a quite old version: 2.1.30
    I'm sorry to be the bearer of bad news, but as my colleague Mark Hayes stressed in a previous post, you really need to upgrade from 2.1.30 to 3.3.latest. It is highly probable that you will eventually run into bugs with 2.x and we are unlikely to (1) be willing to diagnose them, and (2) fix them. As Mark pointed out, 2.1 is 3.5 years old and the product has had a lot of improvements in that time. We are happy to answer questions on this forum relating to the latest major release, but dealing with old and crusty code is certainly going to be well below our allowable priority level.
    Charles Lamb

  • Metalink Ids for hot backup clonning

    Hi i want to perform hot backup clonning in R12 single node to single node and single node to multi node,
    Please tell me the metalink ids

    Please see these docs.
    Cloning Oracle Application 11i /R12 with Rapid Clone - Database (9i/10g/11g) Using Hot Backup on Open Database [ID 760772.1
    Cloning E-Business Suite Using Hot Backup for Minimal Downtime of Source Environment. [ID 362473.1]
    Rapid Clone Documentation Resources, Release 11i and 12 [ID 799735.1]
    RMAN Guides

  • Azure for hot backup

    Hi guys,
    I can't seem to search this scenario.
    Can Azure be used as a Hot Backup? An on-prem server is backed up on the the Azure Cloud. When some disaster befalls the on prem server, can we switch to the cloud server?
    Most document just discusses the backup and restore capabilities of Azure but not as hot backup capabilities.

    Hi Jojo,
    You can backup your op-promise server on Azure Cloud. Please refer to this page about how to configure it:
    But for Azure Backup how to work, I suggest you can post this issue on Azure back up forum for more details.
    We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
    HERE to participate the survey.

  • Shell scripting for hot backup

    can you please give me shell scripting and it's explanation for taking hot backup. and which shell scripts are frequently use in real time.
    thank a lot in advance.

    HAve you ever heard about RMAN ? Much better than reinvent the wheel.

  • RMAN script for hot backup (looking for code critic) code attached.

    Hello Guru's,
    I have been having soem trouble running a successful hot full rman backup nightly.
    We max our CPU load whenever our RMAN takes too long and conflicts with a Legato tape backup. I have a development server that I attempted to get a consistent backup time duration that is rock solid as to not conflict with the Legato backup time.
    I just found out about duration with RMAN scripts here is my code:
    #rman backup script for daily hot whole database backup
    at -f /hd1/rman_scripts/rman_backup 0600 tomorrow
    rman target/
    run {
    allocate channel d1 device type disk format '/path/%U';
    backup duration 1:00 partial minimize load database filesperset 1;
    backup as BACKUPSET tag '%TAG' database;
    backup as BACKUPSET tag '%TAG' archivelog all delete all input;
    delete noprompt obsolete;
    release channel d1;
    It completes the backup, but does not use the 1 hour allocated- it only uses 15 minutes on average and creates many files instead of normally three backup files.
    Here is the results from querying the v$rman_status table for operation,status,start_time:
    RMAN,FAILED, 17-OCT-06 0600
    BACKUP,FAILED,17-OCT-06 0600
    RMAN,FAILED,17-OCT-06 0606
    BACKUP,FAILED,17-OCT-06 0615
    RMAN,COMPLETED,17-OCT-06 1513
    However, the timestamps of the backupset files it creates is:
    06:15 and not 1513?????????????
    RMAN appears to have only taken 15 minutes to create the files, why do I have a completed timestamp from v$rman_status of 1513???
    Please advise and comment, I am just learning RMAN.

    Try to remove the DURATION option in your script.
    Here more details about that part.
    Bye, Aron

  • Is user mode driver mandatory for WDDM 1.1 driver model?

    Dear all,
    I am a fresh newbie in Windows driver development .Only one 3 hours of MSDN search experience in Windows Driver. :(
    Trying to learn how to write a WDDM driver for a very basic graphics card. What I understood is: we require a user mode driver as well as a display miniport driver as per WDDM 1.1 driver model working. But I have also seen an alternative path like the following:
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    Could anyone please answer to my query? I need a very basic driver framework to start with WDDM driver model. Unfortunately, I didn't find any example codes for this category. :( Please please please support.
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    Official answer: WDDM User Mode Driver is always needed.
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    This can be used as a starting point for own WDDM driver development. Such a very limited WDDM kernel mode driver can be developed without having to worry about the topic "WDDM User Mode Driver".
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  • Why is the font size for hot links smaller than other text on some web pages

    On some web sites, the hotlinked words and some words in colour appear in a smaller font than they were designed to be.
    When the web master changed the colour to black on one title at the website noted below, it appeared in the correct size.

    That site is designed that way: font-size: x-small;
    <pre><nowiki> A:link { font-family: Verdana,Tahoma,Arial,Helvetica,Sans-serif,sans-serif; font-size: x-small; color: rgb(0,51,204); font-weight: normal; font-style: normal;}</nowiki></pre>

  • Why we cannot take hot backup if database is in noarchive log mode

    I am aware that if database is in noarchive log mode, we cannot take hot backups and only cold backup is possible.
    I would like to know the technical reason behind this restriction?
    Thank You

    Hot backups are fuzzy backups, inconsistent, in other words, since something is always happening in the database.  When you recover, you restore data files and then apply redo to make the transactions consistent.  You can do a complete recovery or recover to a point in time.  So where does the redo come from?  That's what we call archiving redo logs.  When the online redo gets full, it gets archived.
    In the case of an instance crash, the redo is there in the online redo logs, so Oracle can recover automatically.  Anything beyond that, having to do with storage media, is a media recovery, and requires those archived logs.  So unless you have some other way to get your data back, always run in archivelog mode.
    It is really important to understand the concepts.  Please read the docs.
    It may be worth your while to get a third party backup and recovery book too.

  • No archivelog mode backups

    I am curious if anyone knows of any software out there that can backup a database that is in no archivelog mode while it is running?
    I don't want to do this....but I am curious to see if there is any that I have not heard of for a writeup I am doing.
    Tim Boles

    I've never heard about it.
    RMAN which is (on my point of view) the best tool to Backup Oracle database needs to set the database
    in mount state for Cold Backup.
    Else, about mirror or "business copy", they cannot manage dirty blocks in the buffer. They just manage
    the files on the disk but, while a database is open the datafiles have no reason to be consistent.
    We make clone with Business Copy (HP) for our Backup and we need to have the database in archivelog mode
    and the Tablespaces in Backup mode.
    Best regards,

  • How to take a Hot backup of Oracle database

    1: put the db in archive log mode
    2: set the db_sid to correct one
    3: login to sqlplus
    4: verify the name of the db that you are connected to
    select name from v$database;
    5: check if the db is in archive log made
    select log_mode from v$database;
    if not in archive log mode
    another command to check
    archive log list;
    6: find where on disk oracle writes archive log when it is in archive log mode
    sql> show parameter log_archive_dest_1;
    if the value is found to be 0, that means no values will be recorded, so we need to change it
    sql> alter system set log_archive_dest_1='LOCATION=c:\database\oradata\finance\archived_logs\'
    7: shutdown immediate; < this is done just to prepare the db for hot backups >
    8: startup the db in mount mode
    startup mount;
    ( 3 startup types : nomount - just starts the instance, mount - locates the control files and open up according to the values, open - finds the datafiles from the control files and opens up the db )
    9: put the db in archive log mode
    alter database archivelog;
    10: open the database
    alter database open;
    11: check the status of the db
    select log_mode from v$database;
    SQL> archive log list;
    12: create a directory for archived log
    check if its empty, if empty we need to switch
    sql> alter system archive log current;
    run it 5 times < need to put / and enter > , then check the archive log dir , we will find files
    13: make a table in the database and insert data in it
    create table employees (fname varchar(2));
    check the table
    desc employees;
    insert values
    insert into employees values ('Mica');
    14: tablespace must be in hot backup mode
    check the status
    select * from v$backup;
    if found not active, then we need to change
    we cannot put the db in hot backup mode, unless it is archive log mode
    change to hot backup mode
    alter database begin backup;
    check the status
    select * from v$backup;
    15: now we can only COPY DBF FILES
    copy *dbf <distination location>
    16: need to take the db out to hot backup mode
    alter database end backup;
    17: need to make another archive log switch
    alter system archive log current;
    18: need to copy control files now, need to do a binary bckup
    alter database backup controlfile to '<location>\controlbackup';
    19: insert more values to the table
    insert into employess values ('NASH')
    make another archive log switch : alter system archive log current;
    do the same process for more values
    20 : backup all the archive logs to a new location
    21: shutdown the db and simulate a hw error, delete all the files from the database folder
    22: try to start the sqlplus and db ::: error
    23: copy all the backups to the db dir
    need to copy the control files, rename the binary backup of the control file and make the copies as needed
    24: try to mount the db, error < must use reset logs or noreset logs >
    25: need to do a recovering of the database
    restore the archive logs
    startup mount;
    recover database until cancel using backup controlfile;
    it will ask for a log file :
    yes for recovery
    cancel for cancelling recovery
    26: check status: open the database in readonly
    alter database open read only;
    check the tables to see the data
    shutdown immediate
    shartup mount;
    recover again : recover database until cancel using backup controlfile;
    if oracle is asking for a log that do nto exist , all we have to do is type cancel
    27: open the database
    alter database open;
    need to do reset logs
    alter database open resetlogs;
    28: check the db that you are connected, check the tables
    thanks and regards
    site admin

    A very long list ... let me make it shorter.
    SQL> archive log list;If I see this:
    Database log mode              No Archive ModeI put the database into archivelog mode and leave it there forever.
    If it is in archivelog mode:
    RMAN> TARGET SYS/<password>@<service_name> NOCATALOG
    RMAN> BACKUP DATABASE PLUS ARCHIVELOG;Though there are a lot of things one could do better such as incrementals with block change tracking, creating an RMAN catalog, etc.

  • User hot and Rman hot backup

    During user mode hot backup lots of redo gets generated as the entire block is written when any changes are made to a block which is in hot backup mode.But during Rman hot backup less redo are generated why is this so and whatz the logic invloved? and how oracle recovers the file that has been backed up through Rman.
    Could you please explain me regarding this in detail it will be really helpful.

    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
    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
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    Backup mode has another effect, which is to 'freeze' the checkpoint in
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    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.

  • How to Restore datas in Oracle 10g using hot backup?

    I did Hot backup things (On-line backup) in Oracle 10g (Windows environment)
    Now backup files are stored in physical location..
    How to restore the datas to original location..
    Can any one give the url or command for recovery in ora 10g for hot backup

    Please do not dump all of your work in this forum, and expect volunteers to do it for free!!!
    Dear Great Senior DBA Sybrand Bakker
    What are Oracle Discussion Forums?
    Oracle Discussion Forums is an interactive community for sharing information, questions, and comments about Oracle products and related technologies. Most forums are moderated by product managers, and all of them are frequently visited by knowledgeable users from the community
    oracle forums is not your place for showing “bossing” it is a place where junior to seniors share there knowledge and advices, it means helping and sharing….. Knowledge is for giving ….giving only it will increase… don’t discourage any one like this ……
    There are my Great Seniors (not like u) mainly respected Mr. Jonathan Lewis, Mr. Don Burleson and a lot of oracle nominated ACE members are all giving patiently replay to jr. to sr.
    Obeasley oracle doubts are mostly related to practical issue only……
    Pls try to learn the word meaning of “volunteers”

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