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Re: [linux-lvm] What happens with full snapshots

>    The summary answer to the list of questions below
> is "it works well".

Thanks a lot for this very fast answer!

> > 2.       What happens if there is a problem with a snap? I've heard
> on
> > reboot the snapshots are lost. What if there is a power shortage, so
> > the
> > snap is lost, you boot and the original lv just seeks for the snap?
>     LVM snapshots are NOT lost on reboot.  That information may apply
> to some other type of snapshot mechanism unrelated to LVM, or some
> system could potentially be built on top of LVM which holds snapshots
> in RAM, but in the normal use case snapshots are written to disk
> just like any other data you might write to disk.

Ok I just assume I read something wrong it was about lvm, can't find it
anymore, perhaps someone had a problem on reboot (what could happen when
working and experimenting with computers :-) )
But I also think about trying this:
Do you see any problems here (besides that this snapshot will be definitely
lost)? As said the "real changed data" will be on the disk, just the
snapshot is lost ...

>     LVM can be set to maintain a log of backups of the LVM metadata
> in case you had a power failure or other major "oops" in the middle
> of creating a snapshot or something like that.  The tool "vgcfgrestore"
> can restore the LVM configuration to any of your last X valid
> configurations.  I've used that several times when I've done
> something stupid like deleting an important LVM, as I'm doing a
> lot of weird stuff with LVM.

This point is interesting, fortunately I had no problem with lvm. I use
lvmdump -amd [file] to "backup" my lvm (with metadata), never tried to
restore. Not knowing vgcfgrestore before, from the manpage I assume using
vgcfgbackup is the right tool to backup your metadata, right? I thought of
using lvmdump on a regularly basis to get some dumps, I don't know If they
are useful if something happens. 

You said you deleted some lv? Then a vgcfgrestore will restore the vg and
all data (which was there before) will be accessible again?

Thanks again,

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