[lug] SW Raid question

[dio2002 at indra.com]

> LVM also enables snapshots, which are the greatest thing since sliced
> bread.
>
> Note: LVM snapshots slow down your write performance, as each snapshot
> gets a copy of the original disk block as it's overwritten.
>
> Still worth it though, in my opinion.

Very good point.  I forgot about that.  I'm going to have to read up on
that a bit more and see how that fits into my backup / recovery plan. 
IIRC, there was an aspect of snapshots that was less than intuitive.  And
also that it is false sense of security to believe that it will allow you
to do a live backup on a running mysql db (though the documentation leads
you to believe you can do it).