Always run the <application>pg_upgrade</application> binary of the new server, not the old one.

<application>pg_upgrade</application> requires the specification of the old and new cluster's

data and executable (<filename>bin</filename>) directories. You can also specify

user and port values, and whether you want the data files linkedorcloned

user and port values, and whether you want the data files linked, cloned,orswapped

instead of the default copy behavior.

</para>

to perform only the checks, even if the old server is still

running. <command>pg_upgrade --check</command> will also outline any

manual adjustments you will need to make after the upgrade. If you

are going to be using link or clone mode, you should use the option

<option>--link</option> or <option>--clone</option> with

are going to be using link, clone, copy-file-range, or swap mode, you

should use the option <option>--link</option>, <option>--clone</option>,

<option>--copy-file-range</option>, or <option>--swap</option> with

<option>--check</option> to enable mode-specific checks.

<command>pg_upgrade</command> requires write permission in the current directory.

</para>

<listitem>

<para>

Ifthe <option>--link</option>option was <emphasis>not</emphasis>

Ifneither <option>--link</option>nor <option>--swap</option> was

used, the old cluster was unmodified; it can be restarted.

</para>

</listitem>