Provided are techniques for copying data. A volume container copyset that
includes volume containers is received. A volume container copyset that
includes volume containers is received. Each of the volume containers is
associated with a copyset role, and each of the volume containers
includes zero or more volumes, wherein each of the volumes in a volume
container has the copyset role of that volume container. Sets of volumes
are associated with a replication session, wherein each of the sets of
volumes has one volume from each of the volume containers. Each of the
sets of volumes has volumes associated with a copyset role that is
associated with the volume containers with which each volume is
associated. In response to determining that one of membership of one of
the volume containers and a size of a volume in one of the volume
containers has been modified, one or more corresponding volume containers
in the volume container copyset are automatically modified.