Backu and .arc files

[amolik]

Hello Friends

I have a query related to backups and recovery operations.
I am currently operating windows Nt Server with Oracle 8i.
I have set Database in ArchiveLog Mode with automatic archival enabled.
I have set log_archive_dest_1 and 2 in 2 different drives.
Now As I see In both the directories the no. of files are
increasing which are .ARC files. in zip files format.
My query is till what time these archive files are useful
and at what time they should be deleted since my auto archive is enabled ?
Also I would like to know at what particular interval the data in the
.ARC files is commited to the database.

Thanks
Amol

[brhynold]

Archive files contain all commited transactions. They are only copies of redo log files which capture all commited database transactions.

As long as you are doing full cold backups every night you only have to keep the archive logs files produced between backups

We keep a months worth of archive log files just incase something happens in the database that doesn't surface until after the back up is complete so we can go back and do a point in time recovery. (i.e someone dropped a table accidentally and we don't find otu until after a week)

[nabaig]

You need all the archive files from the time you take a full database backup. Ex: If you do a full back up on Sunday, then you need all the archive files which are generated after the backup.

But it is a good practise to offload at least the previous 1 month's arch files to a tape just in case you have to revert your database to a earlier time.

There is no particular interval where arch files are comitted to the database. They are used only during recovery.

Nizar

[amolik]

Thank you Brent and Nizar

From your replies it seems I should offload the files which are there more than one month. Whats the use of them as well if I am regularly taking a cold backup and dont need to go to the old state. The reason I am asking is currently I am running Export backup every evening (full backup). As application not implemented I dont need to take online backup. If I have ready nbackup with me every day whats the use of that archive files. ?

Amol

[brhynold]

They are for recovery between full backups. If you lose a table or a datafile during the day you can use your full backup to recover the table or datafile then implement the changes that were made after the backup by using the archive log files.

Hope I answered your question.