Re: Summary: Oracle and Disk Mirroring

In article <1994Jul25.150010.23574_at_pyra.co.uk>, Graeme Sargent <graeme_at_pyramid.com> wrote:
>RCronau (rcronau_at_aol.com) wrote:
>: In article <1994Jul19.002644.10921_at_rossinc.com>, davidgi_at_rossinc.com
>: (David J. Gimpelevich) writes:
 

>: >Can any OS mirroring system handle raw partitions?
 

>: I doubt it. I believe that the definition of a raw partition is that the
>: OS file system is bypassed and Oracle manages the physical disk.
>: Therefore, it seems by definition, that OS mirroring is unavailable.
>
>Not so. Certainly it's available with Pyramid's vdisk under DC/OSx. I
>doubt that we are alone. :-)
>

I dont want to get into a "me too" type of thang, but it is possible under most Unix vendors systems (Sequent use a product called Sequent Volume Manager).

>Vdisk works at the device driver level, so it makes no difference
>whether you use the raw device driver or the cooked device driver.
>
>: >sudden power failure during a write
 

>: My guess is that the data would be corrupted on both disks. Mirroring
>: would not provide data recovery capability since power has been lost to
>: the entire system.
>
>No corruption would occur. Oracle would do normal recovery on restart.
 Ditto.
>
>: >sudden disk/controller failure during a write
 

>: I would think that if both disks work off the same controller, the same
>: result with the power failure would happen. However, if two seperate
>: controllers were used, then maybe the one good controller would be able to
>: save the data.
>
>Hopefully rather more certainly than "maybe"! :-)
>
>graeme
>--
>Disclaimer: The author's opinions are his own, and not necessarily
> those of Pyramid Technology Ltd. or Pyramid Technology Inc.
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Cheers,
Karl Funk,
Pre-sales Technical Support.
Sequent UK. Received on Fri Jul 29 1994 - 15:29:02 CEST