Ciao Michele,
> both server (master and standby) need a common directory where read
and write the wal files?
Not necessarily. You can use for instance scp to ship the WAL file from
the master to the standby using the network.
> Just another question about replication: there is the possibility to
build a sync between a 32 and a 64 bit (on linux)?
As stated in the documentation
(http://www.postgresql.org/docs/9.0/static/warm-standby.html), the
hardware architecture must be the same.
Hope this helps.
Ciao,
Gabriele
--
Gabriele Bartolini - 2ndQuadrant Italia
PostgreSQL Training, Services and Support
gabriele.bartolini@2ndQuadrant.it | www.2ndQuadrant.it