so you might want to set authentication to <literal>trust</> in
<filename>pg_hba.conf</>, or if using <literal>md5</> authentication,
use a <filename>~/.pgpass</> file (see <xref linkend="libpq-pgpass">)
- to avoid being prompted repeatedly for a password.
+ to avoid being prompted repeatedly for a password. Also make sure
+ pg_upgrade is the only program that can connect to the clusters.
</para>
</step>
data and executable (<filename>bin</>) directories. You can also specify separate
user and port values, and whether you want the data linked instead of
copied (the default). If you use linking, the upgrade will be much
- faster (no data copying), but you will no longer be able to access your
- old cluster once you start the new cluster after the upgrade. See
- <literal>pg_upgrade --help</> for a full list of options.
+ faster (hard link data files rather than copying them), but you
+ will no longer be able to access your old cluster once you start
+ the new cluster after the upgrade. Link mode also requires that the
+ old and new cluster data directories be in the same file system.
+ See <literal>pg_upgrade --help</> for a full list of options.
</para>
<para>