Re: Redo Log Positioning

I agree with this last scenario. You could also re-create log group 2 on the RAID 1. This way you will have four. Keep increasing the sizes of the logs until you start switching about once every half hour.

If you are running in archive log mode, you will still see some slowness in the system. One, because you will have to write the archive logs to the RAID 5. Also, the system switches logs, it will be writing to one while reading from the other for archiving reasons.

If you are running in archive log mode, the best thing you can do is to break up the RAID 1 set and create two RAID 1's with a single disk in each. Then put the logs 1 and 3 on the first RAID 1 and logs 2 and 4 on the second RAID 1. And have the archives written to the RAID 5. You can also accomplish this by purchasing a couple of new disks which will only cost you about 2k.

Berj

In article <8en44p$o9n$1_at_bob.news.rcn.net>,   "Eugene Firyago" <efiryago_at_bisys.com> wrote:
> Create two new log groups (3 and 4) on RAID1 (mirror) containing of 1
 member
> each and then remove the redo log group 2 from RAID5. So you will
 have 3
> redo log groups at 2 members each: the system will create and
 maintain the
> second "members" on mirror drive for you. Or you can break the mirror
 and
> add second redo log members manually from Oracle. It is advisable for
 better
> performance to allocate redo logs onto raw disk partitions/slices
 because of
> sequentially-written nature of the redo logs. You also need to
 increase the
> size of redo log files if the database statistics indicates wait
 events for
> the archiver process.
>
> Eugene.
>
> <rogerxb_at_my-deja.com> wrote in message news:8emjtg$t78
 $1_at_nnrp1.deja.com...
> > I currently have two redo log files, unmirrored and sized at 2M
 each.
> > When we see intense processing there is a slow down and the error
 log
> > indicates that the bottleneck is the redo logs; they are unable to
> > complete archiving quickly enough when switching from redo 1 to
 redo 2.
> >
> > So I realize I have to re-work the system to at least increase the
 size
> > of the logs, and therefore switch less frequently.
> >
> > Here's my question.
> >
> > I have 5 physical 9.1 Gig drives - split into two raid sets -
> > 2 * 9.1 Gig Raid 1 and
> > 3 * 9.1 Raid 5.
> > The current redo logs are placed one on each of these separate
> > devices.
> > I understand that my Raid 5 is going to be slower when writing the
> > logs, but what I want to know is - how should I lay out my log
 files?
> > I believe The theoretical best is to have three groups with two
> > mirrored members in each, across at least three devices; but I only
> > have two physical devices and one is quicker than the other ......
 any
> > suggestions ??
> > Should I just increase the size of my logs, and allow the operating
> > system to do all the mirroring ???
> >
> > Cheers
> > Rog
> >
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
>
>

Sent via Deja.com http://www.deja.com/
Before you buy. Received on Tue May 02 2000 - 00:00:00 CDT