Re: RAID and Redo Logs

Another thing that you can do to minimize redologs as a bottleneck is to archive from different disks than those to which you are currently writing redo.

This is accomplished by having two sets of disks, and alternating redolog groups among them. When the database switches into a new log group, the archiver starts archiving from the other set of disks, which the database just switched off of. This minimizes I/O load on the current redolog group.

--
Jeremiah Wilton http://www.wolfenet.com/~jeremiah

On Tue, 6 Oct 1998 satar_at_my-dejanews.com wrote:
>
> Ideal situation for redo log groups is to have two seperate disks on two
> seperate controllers with one member of the redo log group residing on the
> first disk while the other member of the redo log group residing on the
> second disk. This is because the redo log files have a high level of I/O. If
> you place the redo log groups on a RAID configuration, then you will take a
> performance hit. For example, RAID5...All writes and reads involve a parity
> caculation.
>
> In article <36170F95.16BD_at_gpu.srv.ualberta.ca>,
> Brian Yan <by2_at_gpu.srv.ualberta.ca> wrote:
> > I was told by a DBA that the disk where the redo log resides should not
> > be configured as RAID. Is it true and why? Thank you in advance!
Received on Tue Oct 06 1998 - 16:43:41 CDT