Document that soft-mounting NFS is not recommended.

doc/src/sgml/runtime.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.409 2008/02/26 18:01:26 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.410 2008/03/21 14:23:37 momjian Exp $ -->
 
 <chapter Id="runtime">
  <title>Operating System Environment</title>
@@ -183,7 +183,8 @@ postgres$ <userinput>initdb -D /usr/local/pgsql/data</userinput>
     Specifically, delayed (asynchronous) writes to the <acronym>NFS</>
     server can cause reliability problems;   if possible, mount
     <acronym>NFS</> file systems synchronously (without caching) to avoid
-    this.  (Storage Area Networks (<acronym>SAN</>) use a low-level
+    this.  Also, soft-mounting <acronym>NFS</> is not recommended.
+    (Storage Area Networks (<acronym>SAN</>) use a low-level
     communication protocol rather than <acronym>NFS</>.)
    </para>