SUMMARY: correct dd syntax?

From: Drexx Laggui (
Date: Tue May 05 1998 - 19:31:51 CDT

Hello world,

Many, many, many thanks to those who took some precious
time of theirs to kindly respond (experiment results below):

Mark <> (Marc S. Gibian)
Rich Kulawiec <>
Matthew Stier <>
Ronald Loftin <> (Syed Zaeem Hosain)

My original question was

On Tue, 5 May 1998, Drexx Laggui wrote:
> For speed and simplicity's sake, I want to backup my entire
> 2 disks on my Solaris 2.5.1 SS5 machine using dd from a single
> command line. I booted up using CDROM for safety reasons and
> I'm using a 4mm tape drive for my 2 x 1GB HDDs.
> Is this OK?
> #dd bs=80b if=/dev/rdsk/cot3dos2 of=/dev/rmt/0mn; \
> dd bs=80b if=/dev/rdsk/cot1dos2 of=/dev/rmt/0m
> Will these work?

Basically I think it did because there were no error messages :-)
But then again, as the respondents unanimously said, my sacrifising
speed and simplicity now is no equal to the pain and grief I might
encounter later because then I would need an identical disk (duuhh,
I forgot about that) and other potential problems.

Anyway, I just used ufsdump 0uf /dev/rmt/0n per raw disk partition
(e.g. ufsdump 0uf /dev/rmt/0n /dev/rdsk/c0t3d0s0). It was more CLI
consuming but only once, during the creation of my script. Of course
I was in single-user mode, but not booting from CDROM 'coz ufsdump
needs to read-write on /etc/dumpdates.

Again, thanks to the wonderful samaritans out there,


Drexx Laggui

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