private static Set<ContentCluster> clustersWithMoreThanOneSearchableCopy(Context context) {
        return context.model()
                      .getContentClusters()
                      .values()
                      .stream()
                      .filter(c -> c.getRedundancy().readyCopies() > 1)
                      .collect(Collectors.toSet());
    }
Validates hnsw settings and warns if using hnsw and having searchable copies > 1 for a content cluster

@author hmusum
config-model/src/main/java/com/yahoo/vespa/model/application/validation/HnswValidator.java