I'm migrating a xen machine (my gallery - g.pechurka.com ) from one machine to another.
I wanted to research from quite a long time what should I use in Linux.
I've got a nice working setup but when you research and test you always makes things better.
So, this night I've researched on if I should do MD raid1 or LVM2 mirroring.
Short answer: MD0 raid1 and Physical Volume over it (as used to now). Sometimes LVM is faster but when using single file. You can have serious problems if you have power failure or disk failure/disconnection when using LVM mirroring. It relies on underneath layer to write caches. For further reading open the link below.
Long answer here: lvm2-mirrors-vs-md-raid-1