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Re: Is there a Linux ghost?



On Wed, Sep 05, 2001, Ori Hanegby wrote about "RE: Is there a Linux ghost?":
> hi
> 
> the "dd" command can give u the functionality u would like, by using the
> input/ouput file as the disk/partition u would like to duplicate.
> for example:
> dd if=<hard disk image backup file> of=/dev/hda bs=300k

But watch out - this can be S-L-O-W for the huge disks (20GB) of today...
Just think about it - if it can copy (read and then write) 5MB a second (I'm
just making up a number) it will take over an hour to copy 20GB...

Usually, much of the disk doesn't need to be copied: only about 2GB will
contain prebundled software (hopefully a Linux system!!), and the rest
can be generated again and again by "mkfs"ing empty file systems, "mkswap"ing
swap partitions, and so on. It's easy to copy only one partition, by copying
/dev/hda1 (for example), not the whole /dev/hda. Of course, you'll need to
copy the partition table first - I recommend sfdisk(8).

Whether such an optimization is worthwhile to you depends on what kind of
installation you're trying to do, and how many times you're going to repeat
the same installation.

Of course, all the replies you got (including this one) assume that both
disks are identical (same capcity, layout, etc.). If they're not, this whole
dd approach probably wouldn't work.

-- 
Nadav Har'El                        |     Wednesday, Sep  5 2001, 17 Elul 5761
nyh@math.technion.ac.il             |-----------------------------------------
Phone: +972-53-245868, ICQ 13349191 |May you live as long as you want - and
http://nadav.harel.org.il           |never want as long as you live.

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