Re: [gentoo-user] Re: Duplicate identical Hard Disk

[Joseph <syscon780@gmail.com>]

On 04/02/10 09:47, walt wrote:
>On 04/02/2010 08:46 AM, Joseph wrote:
>>On 04/02/10 09:42, Neil Bothwick wrote:
>>>On Thu, 01 Apr 2010 19:47:09 -0700, walt wrote:
>>>
>>>>However, if you want to leave both cables connected and change your
>>>>BIOS to boot from 'sdb', you will need to edit some of the files on
>>>>'sdb',
>>>
>>>Check your BIOS first, some allow you to disable individual SATA ports,
>>>so you can disconnect the drive without pulling cables.
>>>
>>>
>>>--
>>>Neil Bothwick
>>
>>Good suggestion, but I'm not sure my motherboard BIOS supports it.
>>I have GA-MA790GP-DS4H motherboard, reading from the manual:
>>
>>it has OnChip SATA Type (SATA2_0 ~ SATA2_3 connectors)
>>Mode: Native IDE
>>RAID
>>AHCI - Advanced Host Controller to enable advanced Serial ATA features such as Native Command Queuing and hot plug.
>>
>>Is it the one AHCI? I've never used it. I'm more interested in configuring it as an auxiliary drive "sdb" to serve as a bootable backup. The box will be installed in a remote location and I'll have an ssh access to it.
>>
>>The box is running in a medical clinic and I'm mostly concern that after the emerge if something happens, I want the user to be able to boot "grub" from second drive, and it will be "sdb" (hd1); but during normal operation, when running from "sda" I want
>>to backup some application files to it so "sdb" stays current.
>
>Ah, well, having only remote access rules out unplugging cables or changing
>BIOS settings unless there is someone at the site who can do those things.
>
>Seems like you would be better off to set up grub on sda so it can boot from
>sda by default, but also so a remote user can just choose sdb from grub's menu.
>That assumes that sda is physically intact enough to load grub from sda.  You
>seem to be more worried about software screwups than hardware failure.  But
>you will need to edit the handful of config files on sdb so all the right
>filesystems will mount correctly.

As I've mentioned earlier I have enough backups on another system, so I'm not much worry about hardware failure.
 From my years of experience with Gentoo, I'm more worry about things working correctly after emerge :-/
I've made list what I need to do, but I'm not sure if this is all:

1.) Boot from external CD
dd if=/dev/sda of=/dev/sdb

2.)
modify (add to) grub.conf on sda
#title boot sda current
title=1st HD sda Kernel Current
root (hd0,0)
kernel /boot/kernel-current root=/dev/sda3

#title boot sdb current
title=2nd HD sdb Kernel Current
root (hd1,0)
kernel /boot/kernel-current root=/dev/sdb3

3.) Modify fstab

You have mentioned to use "rdev" but reading man pages it is only i386, and all my boxes running amd64 (x86_64).

-- 
Joseph