However, if you are going to be running docker on real tin (because thats where the value/speed comes in, if you're on AWS thats a whole 'nother issue) Then you might as well use device mapper for what it was originally designed for: mapping fibre channel. (or iscsi, or SAS [another scsi])
That is assuming you want speed, and have paid enough cash to overcome SPoF in your storage layer (it'll be cheaper and faster than trying to software your way out of it.)
However, if you are going to be running docker on real tin (because thats where the value/speed comes in, if you're on AWS thats a whole 'nother issue) Then you might as well use device mapper for what it was originally designed for: mapping fibre channel. (or iscsi, or SAS [another scsi])
That is assuming you want speed, and have paid enough cash to overcome SPoF in your storage layer (it'll be cheaper and faster than trying to software your way out of it.)