Re: Physical I/O on a SAN or NAS

"JEDIDIAH" <jedi_at_nomad.mishnet> wrote in message news:3fd15feb_2_at_athenanews.com...
> On 2003-12-05, Ryan Gaffuri <rgaffuri_at_cox.net> wrote:
> > We are using an NAS. Are there any conventions to handling Physical
> > I/O distribution on NAS or SANs? They are relatively new. Since we
> > dont control which disk or mount point datafiles go on, we really
> > can't spread out the I/O. Does it matter if we put tables in different
>
> I would expect that there is still some mechanism to divy up logical
> drives among physical drives. You probably want to isolate sequential
> access files from random access ones.
>
> IOW, isolate your online redo logs from your tablespace files.
>
> High latency on redo log writes can really clobber performance.
>

Got it in one. I really don't care these days if people insist in RAID-5 for their data files. I could live with that. But if you make the redo logs share the same devices as datafiles, you're on your own.

As I put it to my students: anything that slows down LGWR is going to be felt by the users.

Regards
HJR

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