How best to copy a boot hard drive?

I am using solaris 2.5.1 x86 and would like to make a mirror copy of my main hard drive (it has /, /usr,/tmp,etc., on it).

I would like to know how best to make a copy of this drive, so that if the one running the system crashes, I can jsut throw the copied drive in there and fire the machine up again.  These are SCSI drives in a Dell 4200.

I don't want to use 'ufsdump' because it requires the drive to be unmounted, and these sytems can't be taken down for long periods of time - do maybe 'dd' would work?

Anyway, a detailed response would be appreciated, including how to make the drive bootable, and what order I need to take to get the os to recognize the blank drive, do I need to format it if its going to be an exact duplicate of the drive I want to copy, etc...

Thanks in advance,

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ahoffmannConnect With a Mentor Commented:
dd bs=1024 count=xxx if=/dev/rdsk/c0t0d0s2 of=/dev/rdsk/c0t1d0s2

where xxx is the disksize in kbytes.
Don't forget to adjust the device names ;-)
racyAuthor Commented:
So just a couple more questions on this and I'll be done with it...I am assuming that 'dd' can be used while the machine is running and not screw anything up?  Also, I have used 'dd' before and seem to recall that the permissions on the copied drive where there a way that I can prevent this?

And, lastly is ther a way to get the OS to recognize the disk without having to do a boot -r or b -r and shutdown the computer?

Thanks again
dd just copies bytes, nothing more or less.
So it does not know anything about permissions, nor files or directories (in the data). You just need access to source and destination (wether they are devices and/or files).

To mount disks without rebooting (cold start !) is somehow unsupported. This is not a problem of the OS, but the hardware part. If you have a SCSI bus which allows "hot-plugging", then it's not a problem. Check your manuals.
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