INITIAL_SUBDISKS_IN_PLEX
EXPAND(plex->sdnos, int, plex->subdisks_allocated, INITIAL_SUBDISKS_IN_PLEX);
plex->sdnos = (int *) Malloc(sizeof(int) * INITIAL_SUBDISKS_IN_PLEX); /* allocate sd table */
bzero(plex->sdnos, (sizeof(int) * INITIAL_SUBDISKS_IN_PLEX)); /* do we need this? */
plex->subdisks_allocated = INITIAL_SUBDISKS_IN_PLEX; /* and we have space for this many */