Re: log_archive_interval

First, I would like to thankyou for all the advises you guys gave in this post.

I read in some books saying that it would be more efficient for Oracle if we can configure that the LGWR would do a log switch when CheckPoint. As the default CheckPoint timeout is 1800, does that mean we better have about 30 minutes for the log switch interval ?

I plan to have to two Archive Log destination, one will be mandatory at local drive, say drive E; the other will be optional, at a network mapped drive, say V on a different node. This is just to serve as a backup of the Archive Log files, as it is recommanded to have two different copies of archive log files. This way I don't have to back up the database using RMAN's command 'backup database plus archivelog', I just need to do 'backup database' to save some time in the backup process.

I am not a dba, but I need to administrate a system that is Oracle 9.2 on a Window 2000 Server. Thanks in advance for taking the patience to help me out.

JW.

"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:41ac2aac$0$17541$afc38c87_at_news.optusnet.com.au...
> John Wood wrote:
> > Hi there,
> >
> > We are running Oracle 9.2 on Window 200 environment. I found that the
> > log_archive_interval for our database is set to 0. Somehow, I read some
> > book, saying that we should never set that parameter to 0.
>
>
> Help me out here... try for accuracy rather than quantity. Your O/S is
> Windows 2000 or Windows 2003?
>
> And the parameter of which you speak would, perhaps, be
> archive_lag_target? Or are you referring to log_checkpoint_interval?
> Because log_archive_interval doesn't actually exist.
>
> > In the normal hour of the day, I can see the redo log files get switched
at
> > around every 2 hours. When the daily script to purge some tables is
run,
> > the log files switch within a minute for two or three times. The
purging
> > deletes about 20K rows of data. I have 3 log groups; each log file is
100M
> > in size.
> >
> > The question is: do I need to specify a value for the
log_archive_interval ?
> > The Two hour log switching seems to be too long.
>
> On what basis do you make that claim?
>
> If two hours is too long, why is that? And what time interval do you
> think you'd be happy with? And why?
>
> If the parameter you are actually asking about is
> log_checkpoint_interval, then that is deprecated in 9i, because the
> fast_start_mmtr_target computes it and sets it automatically (along with
> fast_start_io_target). If you set your own values for the parameter,
> that prevents mttr_target from doing its job.
>
> > Also are 3 log groups good enough to prevent the situation that the LGWR
has
> > to wait for ARC process to finish ?
>
> How long is a piece of string?
>
> Come on: no-one can answer your question. On my laptop, two logs is
> fine. On a busy database, perhaps 5, 6 or more groups would be needed.
> The only way to know is to keep an eye on your alert log and your wait
> events.
>
> > I plan to map a drive through network
> > as an optional destination for the Archive Log destination.
>
> Don't. It will be a recipe for disaster. And it's totally unsupported.
> Archiving should be to a local destination unless you specifically
> implement log_archive_dest_n='Service=XXXX' technology. At which point,
> you need Oracle networking functioning properly, and a standby instance
> to receive the redo.
>
> If you must, then use Windows tools to schedule a periodic copying
> across of a local destination. Do not use Oracle to archive to a remote
> destination unless it's with the 'authorised' mechanisms.
>
> > I noticed in
> > this news group that some user use 4 log group for their system, I
wonder
> > under what situation the system need to configure so.
>
> When three is insufficient and five is excessive!
>
> There are NO magic answers. You work it out for your own database by
> using the rich array of diagnostic tools that Oracle provides.
>
> HJR
>
>
> > Thanks for the advise in advance.
> >
> > JW
> >
> >
> >
Received on Tue Nov 30 2004 - 23:47:04 CST