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Software mirroring

Gareth Gudger
Medium Priority
Last Modified: 2010-04-19
I have set up a software mirror for by boot partition in Windows Server 2003.

1/. I know I can switch the disk around if one fails but it is also my belief that I can modifying the BOOT.INI to allow me to boot to either one without needing to open the case. What would be the correct syntax for two SCSI hard drives?

2/. Once booted off one or the other is there a way to tell which one I am booted off on? Somewhere in computer management maybe? I didn't see anything.
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Back again. As far as I'm aware the only way to check which disk your boot off in a RAID format is a third party util or looking at the Boot.ini file and seeing which disk Windows is using.

in boot.ini you should be able to make a change to a line like this
scsi(0)disk(0)rdisk(0)partition(1) (this being the current set up) to this
scsi(1)disk(0)rdisk(0)partition(1) (this being the new set up - by changing the SCSI number to the second disk's id windows should be able to use this to boot.

Gareth GudgerSolution Architect
Most Valuable Expert 2014
Top Expert 2014


When do I use multi() for SCSI?
Gareth GudgerSolution Architect
Most Valuable Expert 2014
Top Expert 2014


Ok, I figured it out.

I had my second disks SCSI ID set to 4. I set it to 1 and it already matched my boot.ini which I guess was correct in some aspects. I left the boot.ini using multi() instead and this seems to work fine.

Would be nice if disk management would tell you which one you are booted off. A nicety - maybe in Longhorn. :)

I am also wondering if it was partly due to my mirrors becoming unsynchronized as well.

However, I am going to award the points to What90 for the good articles.
it was supposed to be multi() not scsi().

multi is almost always used with ide & scsi so long as the controller supports booting.
On the rare chance you use a scsi drive with a controller which does not support booting, like a 10 year old scsi card intended for accessories instead of real hard drives, it won't boot on that, and thus you'll have to boot off a boot floppy and specify the scsi( ) number.

by the way, the scsi ID of the device is not the number you use in the brackets in the multi ( ) or scsi ( ) commands.
The number needed is the actualy physical number of the device. i.e. the first physical hard drive is 0, the second drive is 1, and so on.

This is why your system worked when you used multi(1) and it booted off the second physical hard drive.

-- smile --

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