Re: Summary: Oracle and Disk Mirroring

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. :-)

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.

: >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

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