turning off <varname>fsync</varname>.
</para>
+ <para>
+ For reliable recovery when changing a cluster from
+ <varname>fsync</varname> off to on, it is necessary to force all
+ modified buffers in the kernel to durable storage. This can be
+ done while the cluster is shutdown or while fsync is on by running
+ <command>initdb --sync-only</command>, running <command>sync</>,
+ unmounting the file system, or rebooting the server.
+ </para>
+
<para>
In many situations, turning off <xref linkend="guc-synchronous-commit">
for noncritical transactions can provide much of the potential