Deleting old index data from solr. But HDD spaces doesn`t free.

[Vitaliy Avdeev]

Hello.
I am deliting old data from solr such way.

                String url = "http://192.168.5.138:8080/apache-solr-1.4.0/";;
                CommonsHttpSolrServer server = new
CommonsHttpSolrServer(url);
                server.setDefaultMaxConnectionsPerHost(200);
                server.setAllowCompression(true);
                server.setMaxRetries(1);

                Calendar cal = Calendar.getInstance();
                cal.roll(Calendar.MONTH, false);
                SimpleDateFormat sdf = new
SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
                String query = String.format("publishedDate:[* TO
%s]",sdf.format(cal.getTime()));
                System.out.println(query);
                server.deleteByQuery( query );
                server.commit();

Data disapears feom index but But HDD spaces doesn`t free.

What I am doing wrong?