Re: Oracle and Raid setup

Hi,

"Noons" <wizofoz2k_at_yahoo.com.au> wrote in message news:42ac0184$0$14455$5a62ac22_at_per-qv1-newsreader-01.iinet.net.au...
> VC apparently said,on my timestamp of 12/06/2005 2:22 PM:
>
>> would perform much better for reads than a single disk might. In fact,
>> performance gain with mirroring was observed as early as in 1985 on
>> VAX/VMS.
>
> and is almost unmeasurable nowadays with much larger
> and much more complex systems.

How so ? My point is that having multiple access paths via independent controllers provides true parallelism both for writes and reads. In a simplistic model I described in my other message, for a two disk configuration, there is about 40% gain in performance for reads and 40 % loss for writes. Obviously, with a mixed load you can have either performance loss or gain. For an equal proportion of reads and writes, performance should be the same as a for a single disk.

>You didn't follow the
> discussion through, did you? VMS and what happened there is
> totally irrelevant nowadays.

What's different ? Are you saying that modern OS's are dumber than the '85 VMS and cannot parallelize read acces to a mirrorred set of disks ? Please clarify what exactly you mean..

Thanks.

VC

>
> --
> Cheers
> Nuno Souto
> in sunny Sydney, Australia
> wizofoz2k_at_yahoo.com.au.nospam
Received on Sun Jun 12 2005 - 07:47:37 CDT