private void deleteBlock(CachedUrl cu) throws IOException {
log.info("deleting " + cu.getUrl());
CachedUrlSetSpec cuss = new SingleNodeCachedUrlSetSpec(cu.getUrl());
ArchivalUnit au = cu.getArchivalUnit();
CachedUrlSet cus = au.makeCachedUrlSet(cuss);
NodeManager nm = au.getPlugin().getDaemon().getNodeManager(au);
nm.deleteNode(cus);
}
