[ale] lvconvert adding mirror speed considerations

[Phil Turmel]

On 12/01/2016 06:16 PM, Lightner, Jeffrey wrote:
> pvmove had been my first thought but we got a vendor recommendation
> to do mirroring instead because if something bad happens in the
> middle of the mirroring (e.g. a reboot) one can resume the mirror but
> might lose data if it were a pvmove.

Crashes or reboots shouldn't be a problem.  pvmove thoroughly
checkpoints its actions stripe by stripe.