backups & cloning

PJ af.gourmet at
Wed Sep 30 01:26:17 UTC 2009

Warren Block wrote:
> 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.
But what does that mean? But ad2s1a has just been newfs'd - so how can
it be dumped if its been formatted? And what exactly does stdout mean?
What is dump doing? outputting what to where exactly? I don't see it or
should I say, understand this at all.and then the restore is from what
to where?
>> 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? 
"write error 10 blocks into volume 1
do you want to restart:"
The first time I tried with -L the error was 20 blocks...
Both the slices for dump from and to are same size (2gb) and certainly
not full by a long shot ( if I reccall correctly, only about 14% is used)

> A long pause while the system makes a snapshot is normal.
And what's this about a snapshot? AFAIK, I'm not making a snapshot;
anyway, there is no long pause except for the dumb look on my face upon
seeing these messages.
As it is, I am currently erasing the brand new 500gb disk on which I
want to restore.
Things started out really bad... don't u;nderstand what is going on. I
installed a minimal 7.2, booted up and turned to another computer to do
some serious work. About 2 hours and 49 minutes later I notice messages
on the 7.2 about a page fault or something like that and then the system
reboots. Obviously with errors... but then I reboot again and it comes
up... I tried som copying from another disk and ended up with the disk
all screwed up... yet the Seagate Seatools for Dos doesnt find any
errors on it; Partition magic found an error but couldn't fix it, so now
Im wiping the whole thing and will try to reinstall tomorrow. Doesn't
make sense.

>> 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.
Sure, I agree... but when things are really complicated... I, at least,
don't know how to separate them when they are quite interdependent.
Thanks for responding.

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