Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD

Packages describing “rbd” as local USE flag

Package “rbd” Flag Description
app-emulation/qemu Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD
app-emulation/ganeti Enable rados block device support via sys-cluster/ceph
app-emulation/libvirt Enable rados block device support via sys-cluster/ceph
sys-block/tgt Add support for ceph block devices
net-libs/xrootd Enable rados block device support via sys-cluster/ceph
sys-block/fio Enable Rados block device support via sys-cluster/ceph
sys-fs/multipath-tools Enable Rados block device support via sys-cluster/ceph

All packages providing a “rbd” USE flag (6)