backups & cloning

Warren Block wblock at
Wed Sep 30 00:13:22 UTC 2009

On Tue, 29 Sep 2009, PJ wrote:

> I am getting more and more confused with all the info regarding backing
> up and cloning or moving systems from disk to disk or computer to computer.
> I would like to do 2 things:
> 1. clone several instances of 7.2 from and existing installation
> 2. set up a backup script to back up changes either every night or once
> a week
> There are numerous solutions out there; but they are mostly confusing,
> erroneous or non functional.
> To start, could someone please explail to the the following, which I
> found here:
> You can move system from disk to disk on fly with
> Code:
> $ newfs -U /dev/ad2s1a
> $ mount /dev/ad2s1a.... /target
> $ cd /target
> $ dump -0Lauf - /dev/ad1s1a  | restore -rf -

> This may be clear to someone; it certainly is not to me.
> As I understand it, newfs will (re)format the slice.
> Ok,  But what is standard out in the above example.  The dump is from
> where to where?

dump is reading /dev/ad1s1a and using stdout for output.
restore is writing to the current directory (/target) and is reading 
from stdin.

> Could someone clarify all this for me?
> So far, I have been unable to dump the / slice, not even with the -L
> option.

It's hard to help without knowing the exact commands you are using and 
the errors they are producing.  Help us to help you by posting them.

> I am trying to dump the whole system (all the slices)except swap
> to a usb (sata2 500gb disk) and then restore to another computer with
> 7.2 minimal installation.

A minimal install makes it easier.  You don't need to copy /tmp, either.

> Slices ad2s1d,e,f and g dump ok to usb. a does not - errors ("should use
> -L when dumping live filesystems)

Right.  So what happens when you use -L?  A long pause while the system 
makes a snapshot is normal.

> Do you have to newfs each slice before restoring?

The first time.  But your minimal install already did that for you.

> But if you are restoring on a running 7.2 system, don't you have to 
> restore to another disk than the one the system is on?

Nope.  You can overwrite the running system.  I restore in /usr, /var, 
and then / order.  Then reboot and you are running the new clone.

> I am beginning to think that you have to have a system running and 
> dumpt to another disk on that system and then remove that disk and 
> install in another box and boot from that? Am I getting close? I know 
> it's a lot to ask, but then, I know you guys are capable...  :-)

It's usually best to limit messages to a single question.

-Warren Block * Rapid City, South Dakota USA

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