Server Hang

[eras mus]

Dear List,

As per your advice after so many attempts of fsck on the partition, fsck is
waiting infinitely for /usr partition /dev/ad4s1e. So I given up fsck.

As someone adviced in the list, I disabled ACPI in setup and when BSD
booted I've chosen the second boot option ACPI disabled.To my surprise
machine came back to normal mode.

With all your help,  the website started and is running fine now. I would
like to take a mirror or exact backup full copy of the Hard Disk (which I
don't belive. It is a 80 GB very old Hard Disk). A desktop PC is used as a
server. So I would like to make the mirror copy of this unstable Hard Disk
to another hard disk. So that in case this hard disk  fails I can replace
the Backup hard disk so that the server will be up in no time.

Is it possible to take such a mirror copy of such a  hard disk so that i
can replace it as a hot swap. I request all of your expertise. How to do
hot swap?please shed some light on it.