Re: Veritas -- do # of spindles really matter ??

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 - 09:57:33 CST