Disk cloning

[Ryan Bair]

Are your active volumes on LVM? If so an LVM snapshot will make this
much easier. (Didn't see this mentioned yet, but it is a huge thread)

On Tue, Jan 20, 2009 at 2:13 PM, Aaron <dell at microchp.org> wrote:
> On Tue, 20 Jan 2009 16:35:30 +0100
>  Renaud MICHEL <renaud.michel.defimedia at gmail.com> wrote:
>>Le mardi 20 janvier 2009 à 14:01, Tino Schwarze a écrit :
>>> > - recreate or copy MBR to sdb (don't know how)
>>>
>>> dd if=/dev/sda of=/dev/sdb bs=512 count=1
>>
>>No, with bs=512 you're gonna overwrite the partition table, which is not
>>what you want, except if you are copying on an identical disk and want
>>exactly the same primary partitions.
>>
>>You must use bs=446 (the 66 last bytes contains the primary partition table)
>>
>>--
>>Renaud MICHEL
>>defimedia S.A.
>>
>
>
> In a few of the other messages he said that downtime was not an option, though it was not stated what specifically was running on this machine.
>
> with the example sda, I would assume this is their system disk.  If they have a default install of MySQL for example, this will likely reside on this disk.
>
> dd is not likely an option with anything that locks files or may have live data in buffers/cache.  I would never use dd to clone a live machine that may have files open on the disk in question.
>
> software raid would make far more sense and is easy to set up.  There are many articles on the web showing how to set up a software raid-1 mirror, break the mirror and then restore it elsewhere.
>
>
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