That e-smith during installation wipes out all the data of the hard-disk is both well
documented and warned about. However, I think you should consider taking some 
steps to protect a Compaq system/diagnostic partition. This partition, normally 
about  10-40 MB contains the software for bios setup and hardware diagnostics 
on most compaq servers and desktops. You get to this software by pressing F10
when the cursor jumps up in the top right coner, just after counting the HW boot
sequence, before loading whatever OS is installed. 
These days one can pick up some real solid Compaq hardware with NIC cards for 
around $100, quite ideal for a e-smith gateway server in my opinion. Just too bad
that you wipe out those partitions so that it is harder to verify that the hardware 
is still in good shape.