Re: lazy old guy asks question
On 2025-08-29, alain williams <addw@phcomp.co.uk> wrote:
> On Fri, Aug 29, 2025 at 02:02:43PM +0100, mick.crane wrote:
>
>> I have my data on a separate disk that I copy to various places every now
>> and again.
>> I guess simplest is original plan ( as have been previously given the
>> incantation ) to get 3 ~200Gb disks and dd to them.
>
> If your purpose is backup - then you are *far* better mounting the disk as a
> file system and then copying files somewhere using tar or cpio. That somewhere
> could be a disk - although something like a USB memory stick would be better as
> these are more robust and smaller than a hard disk.
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).
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.
> Why:
>
> • you are copying the data (your files), not all the other bytes on disk (that
> are useless to you)
>
> • the tar/cpio archive will be readable on a greater number of systems than
> just the ones that support the file system on your disk (prolly ext2/similar)
>
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