Hide disk in linux

["Sistemas Aurensis-Sys Sec" <syssec () aurensis com>]

Hi everyone,

I need to hide a disk device in linux. I want make a disk to disk backup, for example with dd utility

dd if=/dev/hda of=/dev/hdb bs=1k conv=sync,noerror

but I want that this disk can't mounting by anyone. Is this method to make disk to disk backup correct? It have any 
problem?
I don't like that a possible hacker can mount disk device and get information from the backup disk.
The system has installed LIDS on the primary disk, but backup disk (secondary) is not affected.

Can anyone help me about how to hide the secondary disk to can't mount?

Thank's in advance

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