Stephanie wrote:
>
> A little background might help:
> Redo logs record all of the changes to the user objects or system objects
> in a database. When one of them fills up the database switches to the other
> one. And it fills that one up. (Oracle databases have a minimum of 2 redo
> logs). Oracle keeps using as many new redo log files as it has available,
> then it cycles back to the old ones. Depending on the activity in the
> database you could switch redo logs files once every xx minutes or once
> every day.
>
> Running in archive log mode means that after one of these logs fills up,
> the database will copy it to another directory where it's safe and won't be
> reused. However, we all know that the problem is how to manage these
> "offline" redo logs or Archived redo logs. They tend to eat up disk space.
> So you keep some on disk and backup the others to tape and delete them.
>
> When a database becomes corrupt you want / need to recover it to the most
> current point and time possible. You'll need all of the archive logs to do
> that. If you're missing one in the middle you have to recover to before the
> time it used that archive log file. If you're missing the most current ones
> you have to recover to before that time. So, Yes, you need them all. And we
> were getting 2 tape copies of all archive logs (keeping 2 old days + the
> current day on disk) and backing them up each night. We felt that protected
> us from a bad tape or anything else going wrong. We wanted to keep 3 days
> worth on line but we didn't want to use that much disk space and we admited
> that might be a little too overprotective.
>
> Running in archive log mode is for 2 reasons: it allows you to do online
> backups which means that you can keep the database up and going during the
> backup (important for 24x7 shops) and it allows you to recover to the most
> current time possbile . Otherwise you shut down your database, do a "cold"
> backup and you can only recover to the last good "cold" or offline backup.
>
> this is probably more than you wanted to know! hope it helps a little.
>
> Stephanie
OK, this explains a lot, but I still have the following question :
Is it possible to switch this 'archive'-stuff off for a specific period
of time. E.g. before we start a big batch-job , and switch the
archiving back on after the job is done ?
Why this question : I only have 3 Gbyte of space available to place the
archived redo-logs. During normal working days this is more than
enough, but during weekends we start so many batch-jobs who do a great
amount of update's on the database and my 3Gbytes if space isn't enough
to hold all the archived redo-logs.
Thanks in advance
Chris MARREEL.
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Received on Wed Jan 07 1998 - 00:00:00 CST
