I use wmware workstation to run two virtual machines with OpenVZ 2.6.32-042stab108.2 installed on top on CentOS 6.6. I have created another primary partition, /dev/sda4, to configure it as drbd resource. I also created a filsystem on it. The second machine is actually created using the virtual disk of the first one, with changed hostname and eth0 ip address. The drbd configuration file is this:global { usage-count no; } common { syncer { rate 100M; } } resource r0 {         protocol C;         startup {                 wfc-timeout  15;                 degr-wfc-timeout 60;         }         net {                 cram-hmac-alg sha1;                 shared-secret password;         }         on primary {                 device /dev/drbd0;                 disk /dev/sda4;                 address 192.168.18.10:7788;                 meta-disk internal;         }         on secondary {                 device /dev/drbd0;                 disk /dev/sda4;                 address 192.168.18.20:7788;                 meta-disk internal;         } }After creating the resource with drbdadm create-md r0, when I enter service drbd start, I get:Failure: (127) Device minor not allocated.The output of drbdadm dump all might be helpful:[root@primary ~]# drbdadm dump all# /etc/drbd.conf# resource r0 on primary: not ignored, not stackedresource r0 {    protocol               C;    on primary {        device           /dev/drbd0 minor 0;        disk             /dev/sda4;        address          ipv4 192.168.18.10:7788;        meta-disk        internal;    }    on secondary {        device           /dev/drbd0 minor 0;        disk             /dev/sda4;        address          ipv4 192.168.18.20:7788;        meta-disk        internal;    }    net {        cram-hmac-alg    sha1;        shared-secret    danuts;    }    startup {        wfc-timeout       15;        degr-wfc-timeout  60;    }}What is causing this error and how can it be mitigated? Thanks!
DRBD Failure: (127) Device minor not allocated
centos;openvz;replication;drbd