I'm not sure if this makes sense, but I agree with both of you. I think that
the use of AutoRaid technology has a use for certain types of Oracle files,
but other types of Oracle files (i.e. Redos and Rollbacks) should be on
individual disk (possibly striped/mirrored). The problem/benifit with
AutoRaid is that no matter how many LU you configure on it, your still
writing to all the disks. There is no way on an HP Autoraid to specify which
disks is used for a certain LU, so if you have I/O hotspots you can't try
and move them around on the AutoRAID. I have seen several postings on the HP
group that have said that HP's AutoRAID has problem handling sequential
data, so a combination of AutoRAID and JBODs may be your best solution.
JH
John Ott <johnott_at_earthlink.net> wrote in message
news:387F476D.B9081B01_at_earthlink.net...
>
>
> rob van laarhoven wrote:
>
> > >>The question:
> > >>Which is faster -- (a) the current 2-spindle architecture, or (b) if 5
> > >>separate filesystems were explicitly-defined on their own dedicated
disk?
> > >>Keep in mind both (a) and (b) would take advantage of the same
> > Veritas/RAID
> > >>configuration (striping and mirroring).
> > >>
> > >
> > IMHO there should be a 1 to 1 relation between mountpoints and physical
> > disks. This will not make the disks faster but will make it possible to
> > place databaseobjects on a specific physical disk, this will be handy
when
> > distributing IO over the disks..
>
> I respectfully disagree.
>
> You can manage this by having the DBA create a logical structure
> and then do the stripping and mirroring you want using Veritas
> or whatever volume management software you are using.
>
> This also makes sense for when you upgrade your hardware. Just
> backup the logical volumes, then set up the new hardware
> and take advantage of its features and present logical volumes
> to the database for the restore.
>
> In some cases you can't get a spindle to define a mount point.
> For instance if you are using a HP autoraid array or a Hitachi 7700e.
> These and other RAID hardware present logical drives to the OS.
> So you can't get a spindle if you wanted to. Many RAID systems
> keep a lot of data in RAM anyway.
>
> So with the advances in Hardware RAID defining I/O layout
> at the Database level is not as important as it used to be.
> And in many cases doesn't make sense at all.
>
> Let the DBA worry about speeding up the
> applications. Let the RAID hardware and software speed
> up I/O.
>
> later
> John
>
>
>
Received on Fri Jan 14 2000 - 22:08:47 CST
