<para>

If you have Streaming Replication (see <xref

linkend="streaming-replication">) or Log-Shipping (see <xref

linkend="warm-standby">) standby servers, follow these steps to

upgrade them. You will not be running <application>pg_upgrade</>

on the standby servers, but rather <application>rsync</> on the

primary. Do not start any servers yet.

linkend="warm-standby">) standby servers, and used link mode,

follow these steps to upgrade them. You will not be running

<application>pg_upgrade</> on the standby servers, but rather

<application>rsync</> on the primary. Do not start any servers yet.

If you did <emphasis>not</> use link mode, skip the instructions in

this section and simply recreate the standby servers.

</para>

<substeps>

<title>Run <application>rsync</></title>

<para>

From a directory on the primary server that is above the old and

new database cluster directories, run this on the

<emphasis>primary</> for each standby server:

When using link mode, standby servers can be quickly upgraded using

<application>rsync</>. To accomplish this, from a directory on

the primary server that is above the old and new database cluster

directories, run this on the <emphasis>primary</> for each standby

server:

<programlisting>

rsync --archive --delete --hard-links --size-only old_pgdata new_pgdata remote_dir

</programlisting>

where <option>old_pgdata</> and <option>new_pgdata</> are relative

to the current directory on the primary, and <option>remote_dir</>

is <emphasis>above</> the old and new cluster directories on

the standby. Theold and new relative cluster paths

must matchon the primary andstandby server. Consult the

is <emphasis>above</> the old and new cluster directories

onthe standby. Thedirectory structure under the specified

directorieson the primary andstandbys must match. Consult the

<application>rsync</> manual page for details on specifying the

remote directory, e.g. <literal>standbyhost:/opt/PostgreSQL/</>.

remote directory, e.g.

<programlisting>

rsync --archive --delete --hard-links --size-only /opt/PostgreSQL/9.5/data \

/opt/PostgreSQL/9.6/data standby.example.com:/opt/PostgreSQL

</programlisting>

</para>

<para>

What <application>rsync</> does is to copy files from the

primary to the standby, and, if <application>pg_upgrade</>'s

<option>--link</> mode was used, link files from the old to

new clusters on the standby. It links the same files that

<application>pg_upgrade</> linked in the primary old and new

clusters. (Of course, linking speeds up <application>rsync</>.)

Unfortunately, <application>rsync</> needlessly copies files

associated with temporary and unlogged tables because these files

don't normally exist on standby servers.

What this does is to record the links created by

<application>pg_upgrade</>'s link mode that connect files in the

old and new clusters on the primary server. It then finds matching

files in the standby's old cluster and creates links for them in the

standby's new cluster. Files that were not linked on the primary

are copied from the primary to the standby. (They are usually

small.) This provides rapid standby upgrades. Unfortunately,

<application>rsync</> needlessly copies files associated with

temporary and unlogged tables because these files don't normally

exist on standby servers.

</para>

<para>

If you have tablespaces, you will need to run a similar

<application>rsync</> command for each tablespace directory. If you

have relocated <filename>pg_wal</> outside the data directories,

<application>rsync</> must be run on those directories too.

<application>rsync</> command for each tablespace directory, e.g.:

<programlisting>

rsync --archive --delete --hard-links --size-only /vol1/pg_tblsp/PG_9.5_201510051 \

/vol1/pg_tblsp/PG_9.6_201608131 standby.example.com:/vol1/pg_tblsp

</programlisting>

If you have relocated <filename>pg_wal</> outside the data

directories, <application>rsync</> must be run on those directories

too.

</para>

</step>