[gentoo-user] Migrating a system

[gentoo-user] Migrating a system

[Randy Barlow]

So I was an idiot when I set up my system and didn't use LVM.  Now that 
I'm out of disk space on one of my drives and kicking myself, I want to 
do it without doing a reinstall.  If I use tar -cvjpf 
oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 /, then setup LVM, then 
tar all that junk back to the new system via tar -xvpf 
oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 with / as my working 
directory, should that do the trick (with, of course, another go at 
grub-install)?  Is the -p flag to tar enough to store ALL the necessary 
file system information?  I just want to make sure I'm not forgetting 
anything...

P.S.  And I'll have to build LVM support into the kernel too...

R
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Re: [gentoo-user] Migrating a system

[Daniel Pielmeier]

Randy Barlow schrieb:
> So I was an idiot when I set up my system and didn't use LVM.  Now that
> I'm out of disk space on one of my drives and kicking myself, I want to
> do it without doing a reinstall.  If I use tar -cvjpf
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 /, then setup LVM, then
> tar all that junk back to the new system via tar -xvpf
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 with / as my working
> directory, should that do the trick (with, of course, another go at
> grub-install)?  Is the -p flag to tar enough to store ALL the necessary
> file system information?  I just want to make sure I'm not forgetting
> anything...
> 
> P.S.  And I'll have to build LVM support into the kernel too...
> 
> R

>From time to time i backup my complete system to avoid a reinstall after
failures. I used something like this and it worked for me (tested it
after a hard drive crash)!

tar --atime-preserve --same-owner --numeric-owner -Spvcjf back.tar.bz2 /

Maybe some flags are not necessary but --same owner would be a good
option to preserve the user and group permissions of the files too, as i
don't know if -p already covers this.

Also take care to mount all partitions you want to backup!

I don't know about lvm as i did not use a logical-volume-manager this
time and now i use lvm within evms.
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Re: [gentoo-user] Migrating a system

[Randy Barlow]

Daniel Pielmeier wrote:
> tar --atime-preserve --same-owner --numeric-owner -Spvcjf back.tar.bz2 /

Is it really necessary to back up /sys and /proc?  What about /dev?
Also, to Björn, I didn't find a -a option in man tar, what does it do?
Is it different that --atime-preserve?  Thanks!

-- 
Randy Barlow
http://electronsweatshop.com
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Re: [gentoo-user] Migrating a system

[Daniel Pielmeier]

Randy Barlow schrieb:
> Is it really necessary to back up /sys and /proc?  What about /dev?

I don't think it is necessary but it will consume almost no disk space
so I don't worry.

> Also, to Björn, I didn't find a -a option in man tar, what does it do?

Didn't find this option too!

> Is it different that --atime-preserve?  Thanks!
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Re: [gentoo-user] Migrating a system

[Mick]

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On Wednesday 03 October 2007, Daniel Pielmeier wrote:
> Randy Barlow schrieb:
> > Is it really necessary to back up /sys and /proc?  What about /dev?
>
> I don't think it is necessary but it will consume almost no disk space
> so I don't worry.
>
> > Also, to Björn, I didn't find a -a option in man tar, what does it do?
>
> Didn't find this option too!
>
> > Is it different that --atime-preserve?  Thanks!

Run tar from a LiveCD to back up the fs' in each partition.  Virtual fs won't 
bother you then.
-- 
Regards,
Mick

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Re: [gentoo-user] Migrating a system

[Neil Bothwick]

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Hello Daniel Pielmeier,

> > Is it really necessary to back up /sys and /proc?  What about /dev?  
> 
> I don't think it is necessary but it will consume almost no disk space
> so I don't worry.

/proc/kcore can get rather large. You are not only using the disk space
when backing up, but when restoring too. If you have 4GB of RAM, you will
waste 4GB of your root partition when you restore /proc/kmem, which could
be a problem if root is only a few hundred MB.

The --one-filesystem option would be useful here. I prefer to back up
each filesystem separately, since the main planned use for them is a
hosed filesystem I would hope to need only one of them (at most).


-- 
Neil Bothwick

We are sorry, but the number you have dialed is imaginary.

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Re: [gentoo-user] Migrating a system

[Björn Ottervik]

On Tue, 2007-10-02 at 16:45 -0400, Randy Barlow wrote:
> So I was an idiot when I set up my system and didn't use LVM.  Now that 
> I'm out of disk space on one of my drives and kicking myself, I want to 
> do it without doing a reinstall.  If I use tar -cvjpf 
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 /, then setup LVM, then 
> tar all that junk back to the new system via tar -xvpf 
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 with / as my working 
> directory, should that do the trick (with, of course, another go at 
> grub-install)?  Is the -p flag to tar enough to store ALL the necessary 
> file system information?  I just want to make sure I'm not forgetting 
> anything...
> 
> P.S.  And I'll have to build LVM support into the kernel too...
> 
> R

The -a option might be a good choice, and i like the --one-file-system
as well, for backup purpouses. Its very convenient to be able to restore
partitions separatly, without having to remember whats mounted where and
'what parts of this and that did I archive'.
rsync is nice too. And faster... Just remember not to rsync to a non
UNIX FS, as that would cause some troubles with permissions and other
things.

Good luck. :)

/Björn

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Re: [gentoo-user] Migrating a system

[Dan Farrell]

On Tue, 02 Oct 2007 16:45:23 -0400
Randy Barlow <randy@electronsweatshop.com> wrote:

> So I was an idiot when I set up my system and didn't use LVM.  Now
> that I'm out of disk space on one of my drives and kicking myself, I
> want to do it without doing a reinstall.  If I use tar -cvjpf 
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 /, then setup LVM,
> then tar all that junk back to the new system via tar -xvpf 
> oldSystemThatShouldStillWorkWhenUnTarred.tar.bz2 with / as my working 
> directory, should that do the trick (with, of course, another go at 
> grub-install)?  Is the -p flag to tar enough to store ALL the
> necessary file system information?  I just want to make sure I'm not
> forgetting anything...
> 
> P.S.  And I'll have to build LVM support into the kernel too...
> 
> R

You could always just move a few very large or very critical pieces of
the filesystem (like /home) over to a new drive.  Then you'd have lots
of extra space and you'd have a backup disk to use in case your primary
went down.  You could also back up the primary stuff on an unmounted
backup partition on the second drive, effectively providing an
almost-hot backup.  

BTW, I highly recommend not compressing the archive
>...tar.bz2 
because it will take a really long time.  Just tar it and leave it at
that.  It might be a few hundred megs bigger, but it'll get done before
december.  
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