Re: looking for archivelog info

In article <39de2ce2_3_at_news.cadvision.com>,   "Clement Yuen" <clem_yuen_at_yahoo.com> wrote:
> Hi
>
> I am a newbie to oracle.
> Can anyone give me some information on archivelog?
>
> I would like to know if it effects performance and if it take tons of
 HD
> space?
>
> Any info would be appreciated.
>
> Thanks
> Clem:)
>
>

In a manner of speaking archivelog mode does effect performance (it allows you to recover an instance or a tablespace should failure occur), but I believe you meant to ask if it affects performance. It does, but the affect is usually slight. The added "comfort factor" of running in archivelog mode versus noarchivelog mode is definitely worth the trouble.

Depending upon the activity against your instance archive logs can consume quite large amounts of disk space; this is precisely why a nightly job is scheduled to take the archived logs to tape or other removable media so that they may be removed from the server to allow the next run of archived redo logs to be written. It is recommended that you supply at least two days worth of space for archive logs, giving you a cushion in the event of hardware failure (tape drive, Zip drive, JAZ drive, etc.) and you cannot remove the archive logs. Another method, for extremely active databases, is to periodically compress the archive logs to create more space in the directory. You will then be able to store more than two days worth of logs on a disk; you will STILL need to take the compressed logs to tape (or other removable media) lest you fill up the archive log destination and bring the database to an abrupt halt.

--
David Fitzjarrell
Oracle Certified DBA


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