[Qemu-devel] What kind of situation to use internal or external snapshot?

[lampahome]

as title, I know there're two snapshots in qemu, but I don't know when to
use them well.

What I know is internal snapshot will save the info of L1 and L2 table in
the end of image but external snapshot won't because external snapshot
create new file to save cow data.

So when to use internal snapshot or external snapshot?

thanks to everyone.