Re: Cascade streaming replication + wal_files - Pgsql 9.2

the only way to archive the wal_files from a slave into another slave on PostgreSQL 9.2, is by using pg_reveivexlog?

Yes. Though I have never tried this myself but going by the theory, it should work.

a slave doesn't generate wal_files at all.

if your master is keeping a wal_archive, slaves, including cascaded streaming slaves, can all use that same archive as their wal source, these are only used for catchup when streaming is interrupted.   

-- 
john r pierce, recycling bits in santa cruz