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Backup and restoration

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allan Faylona
Occasional Contributor

Backup and restoration

I have a test database. MY database archive is set to norarchivelog mode. If my db is available on Monday morning, and made changes from Monday afternoon to friday afternoon and make a full backup on friday night. Will I able to restore the db with the changes I made from Monday afternoon to friday afternoon?

Regards,
Allan
6 REPLIES
Patrick Wallek
Honored Contributor
Solution

Re: Backup and restoration

How are you backing it up? Is the DB still up when you do the backup? If so, it is very likely that whatever backup you do is utterly useless.

For databases, at least Oracle, it is recommended to either:

1) Do a cold backup. This is where the DB is shutdown completely so no one can access it.

2) Do hot backups. This where your DB is in archivelog mode and you put the tablespaces in Backup Mode, then back them up, the take them back out of backup mode.

3) Utilize Oracles RMAN utility to help with backups. Most 3rd party backup products can interface with RMAN.

Any other methods used run the risk of not having valid backups.
Rick Garland
Honored Contributor

Re: Backup and restoration

How are you doing the backup?

You state that archiving is off so the backup of the database needs to be done 'COLD' in order to have a good backup of the DB.

If this is done then you will have a good backup and those changes will be present.

If archiving is on then you can put the database into BACKUP MODE, backup the database, backup the archive logs, then when you do a restore you can lay down the DB and the archive logs and the DBAs can apply the archive logs to the DB.

If archiving is off, a good DB backup is a COLD DB during the backup.
allan Faylona
Occasional Contributor

Re: Backup and restoration

I'll be doing a cold backup. So it means the changes will still be recorded during the time of restoration. Of course I have to consider a good backup.

Regards,
Allan
Patrick Wallek
Honored Contributor

Re: Backup and restoration

Since you are doing a cold backup, the database will be restored to the same state as when it was backed up. So, yes, any changes that occurred during the week will still be there.
Jean-Luc Oudart
Honored Contributor

Re: Backup and restoration

Allan,


if the database was properly shut down before the full backup (COLD backup) you should have a proper backup copy of your database as for Friday evening.

If you need hot backup you should use RMAN
http://www.oracle.com/technology/deploy/availability/htdocs/RMAN_Overview.htm

Regards
Jean-Luc
fiat lux
Simon Wickham_6
Regular Advisor

Re: Backup and restoration

Hi Allan,

A cold backup is a physical backup.
During a cold backup the database is closed and not available to users. All files of the database are copied.The datafiles do not change during the copy so the database is in sync upon restore.

Depending on your requirements it is relatively straight forward to place your system into nonarchivelog mode and use the control file instead of a catalog.

Uncomment or just appent the following example.

log_archive_start = TRUE
log_archive_dest_1 = 'LOCATION=/arch_dir_name'
log_archive_dest _state_1 = ENABLE
log_archive_format = %d_%t_%s.arc

Issue the following commands to put a database into ARCHVELOG mode:

SQL> CONNECT sys AS SYSDBA
SQL> STARTUP MOUNT EXCLUSEVE;
SQL> ALTER DATABASE ARCHIVELOG;
SQL> ARCHIVE LOG START;
SQL> ALTER DATABASE OPEN;

Regards,
Simon