I can't seem to figure out which steps I need to do, to get the standby server wiped and get it started as a streaming replication again from scratch. I tried to follow the steps, from step 6, in here http://wiki.postgresql.org/wiki/Streaming_Replication but the process seems to fail when I reach the point where I try to do a psql -c "SELECT pg_stop_backup()". It just says:
If you use pg_basebackup you don't need to manually put the master into backup mode. Be aware that if you are generating a lot of WAL segments and your filesystem backup is large (and takes a while to ship to the slave), you will need to set "wal_keep_segments" quite high on the master to prevent the segments from disappearing during the setup of the slave -- or at least that's the case when you use "--xlog-method=stream".