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Re: lazy old guy asks question



On Fri, Aug 29, 2025 at 03:57:42PM -0000, Greg wrote:

> Yes. I don't understand what he is trying to achieve beyond using dd
> because it's cool or something. Maybe it is cool. My understanding is that it
> produces a byte for byte copy (my understanding without looking anything
> up). 

Your understanding is correct.

> Now, I am fuzzy on a RAID array (the OP's question calls this to my
> mind), which I think is a series of disks with the same content so that
> if one fails, you can replace it with another. But not to be used as a
> backup strategy.

+1

RAID is NOT backup - if you delete a file on a RAID-1 (mirror) system then the
file is deleted on both mirrors. Much the same on other RAID levels.

RAID is to allow the system to continue when there is a hardware failure.

If you have RAID you still need to do daily/... backups using tar/cpio/...
to a removable tape/disk/... (preferably taken to an off-site location).

Sorry for repeating what you said, but many people do not understand this.

Regards

-- 
Alain Williams
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