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On 04/01/2010 06:40 PM, Joseph wrote: |
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> On 04/01/10 17:43, Mark Knecht wrote: |
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>> On Thu, Apr 1, 2010 at 4:02 PM, Paul Hartman |
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>> <paul.hartman+gentoo@×××××.com> wrote: |
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>>> On Thu, Apr 1, 2010 at 5:48 PM, Joseph <syscon780@×××××.com> wrote: |
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>>>> I have two identical HD in the box and want to duplicate sda to sdb; |
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>>>> sdb is not even partitioned. |
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>>>> I think I could do: |
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>>>> dd if=/dev/sda of=/dev/sdb |
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>>>> but I need to boot from CD isn't it? |
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>>> |
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>>> Yes, basically, boot from USB or CD and use ddrescue to clone it, then |
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>>> edit your fstab and I think you should be good. |
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>>> |
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>>> RAID1 would help if a drive physically dies, but if you had any |
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>>> filesystem corruption or anything you'd just have an identically |
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>>> corrupt copy on the second disk. |
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>> |
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>> A big part of my struggles over the last few days has been with mdadm |
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>> & RAID1. I'm learning that we don't want to send someone down that |
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>> path unless he has the right sort of disks. I'm having to deal with |
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>> returns and reordering due to this. |
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>> |
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>> People should be aware of what is really required to do RAID before |
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>> they get started so they don't duplicate my trials. I wasn't and I'm |
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>> paying for it. (Almost literally if I don't get the drives in the |
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>> mail!) ;-) |
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>> |
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>> Cheers, |
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>> Mark |
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> |
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> So what you are folks saying is to stay away from RAID-1, beside as Paul mention if I get any corruption and/or configuration (due to ebuild) with RAID I'll be screwed anyhow. |
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> So my best option is bootable CD and: |
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> dd if=/dev/sda of=/dev/sdb |
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> |
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> But I'm kind of confused as to how to edit the "sdb" second drive. |
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> I know I'll have to edit at lest: grub.conf and fstab |
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> But how? |
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> |
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> 1.) Both disk are bootable, (have a boot sector) if I disconnect first one sda, I think the second one will be recognize automatically as "sda" isn't it? |
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> 2.) If configure second drive after copying as "sdb" will it still boot if fist disk is disconnected? |
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|
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In the old days you had to be careful about configuring each drive as either |
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'master' or 'slave'. That was the old PATA drives. Today, most drives are |
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SATA drives (a very good thing) so you don't have to worry about those silly |
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jumpers on the back of each drive. No such thing as 'master' or 'slave' any |
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more :o) |
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|
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So, assuming your drives are SATA drives, all you need to do is to unplug |
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the cable from one drive and the other drive will automatically be sda when |
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you reboot. In that case you don't need to edit any files at all because the |
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drive that you plugged in is automatically sda, no matter which drive it is. |
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|
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However, if you want to leave both cables connected and change your BIOS to |
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boot from 'sdb', you will need to edit some of the files on 'sdb', just as |
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you said, including all appropriate entries in fstab, and the 'root' device |
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in grub.conf (e.g. change hd0 to hd1), and use the 'rdev' utility to change |
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the 'root device' in your /boot/vmlinuz-2.6.NN file. (man rdev). |
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