@ca = qw (ma mb mc md me mf mg mh); # 8-node cluster
@cb = qw (mi mj mk ml mm mn mo mp); # 8-node cluster
@cc = qw (mq mr ms mt);             # 4-node cluster
@cd = qw (mu mv mw mx);             # 4-node cluster
@ce = qw (my mz);                   # 2-node cluster
@cf = qw (m1 m2);                   # 2-node cluster
@cg = qw (m3 m4);                   # 2-node cluster
@ch = qw (m5);                      # standalone
@ci = qw (m6);                      # standalone
@cj = qw (m7);                      # standalone
@ck = qw (m8);                      # standalone