[gentoo-user] VFAQ mirroring a live root FS

[gentoo-user] VFAQ mirroring a live root FS

[Helmut Jarausch]

Hi,

would anybody please explain to me what difficulties
might occur if I mirror a live root file system
and use that for booting (in an emergency case).

I know that for proper mirroring I may mirror a live
root file system but I have to rsync it after booting from a 
different device (USB,...)

But what happens if I have to boot a system from a backup
which has been mirrored from a live root file system.

Many thanks for sharing your experience,
Helmut.

Re: [gentoo-user] VFAQ mirroring a live root FS

[Daniel Troeder]

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On 07/01/2010 05:12 PM, Helmut Jarausch wrote:
> Hi,
> 
> would anybody please explain to me what difficulties
> might occur if I mirror a live root file system
> and use that for booting (in an emergency case).
> 
> I know that for proper mirroring I may mirror a live
> root file system but I have to rsync it after booting from a 
> different device (USB,...)
> 
> But what happens if I have to boot a system from a backup
> which has been mirrored from a live root file system.
> 
> Many thanks for sharing your experience,
> Helmut.


This will probably be no problem at all: it's (nearly) the same thing as
pushing the reset knob and booting :)

I suggest you use a LVM-snapshot. If you use "cp" or "rsync", then use
the "-x" switch (and "-S" with rsync). Those methods have worked for me
for bare-metal-recovery until now.

The only thing that mostly breaks are databases. So create a dump before
copying, and copy it too. Or if possible stop the DB and make a copy of
the files, then start it again. Or both ;)

Bye,
Daniel


Just in case: When booting from CD always use "--numeric-owner" with tar
and "--numeric-ids" with rsync or uids and gids will get messed up.

-- 
PGP key @ http://pgpkeys.pca.dfn.de/pks/lookup?search=0xBB9D4887&op=get
# gpg --recv-keys --keyserver hkp://subkeys.pgp.net 0xBB9D4887


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