[DRBD-user] single-disk nodes replicated in a multi-disk nas

[Antonio Anselmi]

I'm wondering if could be possible run DRBD in such scenario:

- n single disk nodes
- one nas equipped with n+1 disks
- all the disks have the same dimensions and geometry

so that in a 3-1 deployment (3 nodes and one nas with 4 disks) the
drbd.conf files could be the following

*node1 /etc/drbd.conf:
global { usage-count yes; }
common { syncer { rate 10M; } }
resource rA {
    protocol C;
    meta-disk internal;

    on node1 {
        address 10.0.0.1:7789;
        device /dev/drbd0
        disk /dev/sda;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd0
        disk /dev/sdb;
    }
}

*node2 /etc/drbd.conf:
global { usage-count yes; }
common { syncer { rate 10M; } }
resource rB {
    protocol C;
    meta-disk internal;

    on node2 {
        address 10.0.0.2:7789;
        device /dev/drbd0
        disk /dev/sda;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd1
        disk /dev/sdc;
    }
}

*node3 /etc/drbd.conf:
global { usage-count yes; }
common { syncer { rate 10M; } }
resource rC {
    protocol C;
    meta-disk internal;

    on node3 {
        address 10.0.0.3:7789;
        device /dev/drbd0
        disk /dev/sda;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd2
        disk /dev/sdd;
    }
}

*nas /etc/drbd.conf:
global { usage-count yes; }
common { syncer { rate 10M; } }

resource rA {
    protocol C;
    meta-disk internal;

    on node1 {
        address 10.0.0.1:7789;
        device /dev/drbd0
        disk /dev/sda;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd0
        disk /dev/sdb;
    }
}

resource rB {
    protocol C;
    meta-disk internal;

    on node2 {
        address 10.0.0.2:7789;
        device /dev/drbd0
        disk /dev/sdc;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd1
        disk /dev/sdd;
    }
}

resource rC {
    protocol C;
    meta-disk internal;

    on node3 {
        address 10.0.0.3:7789;
        device /dev/drbd0
        disk /dev/sda;
    }
    on nas {
        address 10.0.0.10:7789;
        device /dev/drbd2
        disk /dev/sdc;
    }
}

The single resources rA rB and rC are respectively defined in the
nodes node1, node2 and node3 and are grouped inside the drbd.conf of
the nas.

Is that correct?

Antonio