Re: multiplexing online redo logs

"Pete Sharman" <peter.sharman_at_oracle.com> wrote in message news:aslagp01pth_at_drn.newsguy.com...
> In article <asl6ie$aim$1$8302bc10_at_news.demon.co.uk>, "Alistair says...
> >
> >Hi
> >
> >Connect as system and try an
> >
> >sql> alter system switch logfile;
> >
> >then check
> >
> >sql> select * from v$log;
> >
> >Alistair
> >
> >"Uwe" <uwe.embshoff_at_lit.lineas.de> wrote in message
> >news:3e9b0c3d.0212040707.2667cf27_at_posting.google.com...
> >> Hello,
> >>
> >> I want to multiplex my online redo logs on different disk. I used the
> >> following command to create an additional member for each of my 3 redo
> >> log groups:
> >>
> >> ALTER DATABASE ADD LOGFILE MEMBER
> >> '/usr2/oracle/mnt2/oradata/ws93/redo01.log' TO GROUP 1;
> >>
> >> To me, this doesn't seem to be enough, because when I change some
> >> data, these files are not updated. Only the initial redo log files are
> >> updated. When I look into v$logfile, they are "invalid". How can I set
> >> them to valid?
> >>
> >> Thank you!!!
> >> Uwe
> >
> >
> Perfectly true, but also unnecessary. All that the status of INVALID
means is
> that the file is either inaccessible OR that Oracle has not attempted to
access
> it yet. While switching log files with an ALTER SYSTEM command will clear
this
> status, so will normal operation of the database causing log switches to
take
> place. All you really get by using the ALTER SYSTEM command is a warm
fuzzy
> feeling inside. :)
>

Hi Pete,

The only comment I would add is that assuming you've just seen the light and decided to multiplex your redo logs, the *current* group is still going to be "on it's own" as the new member will have no effect until the group is written to again.

Performing a redo log switch to the next group means that as of *now*, your generated redo finally has the protection it deserves in that all subsequent redo is multiplexed.

That, and also the fact I can do with all the warm fuzzy feelings I can get ...

Cheers

Richard Received on Thu Dec 05 2002 - 07:45:12 CST