ERRO[0000] [graphdriver] prior storage driver "devicemapper" failed: expected integer FATA[0000] Error starting daemon: error initializing graphdriver: expected integer

Hi,

i am trying to start docker with following options:

docker --daemon=true --selinux-enabled -l debug --storage-opt dm.thinpooldev=/dev/mapper/konohaVG-docker–pool

It results in the following error:DEBU[0000] devicemapper: driver version is 4.29.0
DEBU[0000] Generated prefix: docker-253:4-59719757
DEBU[0000] Checking for existence of the pool 'konohaVG-docker–pool’
ERRO[0000] [graphdriver] prior storage driver “devicemapper” failed: expected integer
FATA[0000] Error starting daemon: error initializing graphdriver: expected integer

Does anybody know this failure and how to resolve it ?

Thanks
Docker version 1.8.3
Kernel: 3.10.0-229.14.1.el7.x86_64