Implement sync option

[nbd.git] / nbd-server.5.sgml

diff --git a/nbd-server.5.sgml b/nbd-server.5.sgml
index fecbc61..fa9b321 100644 (file)
--- a/nbd-server.5.sgml
+++ b/nbd-server.5.sgml
@@ -174,23 +174,6 @@ manpage.1: manpage.sgml
        </listitem>
       </varlistentry>
       <varlistentry>
-       <term><option>autoreadonly</option></term>
-       <listitem>
-         <para>Optional; boolean.</para>
-         <para>
-           If this option is set to true, then
-           <command>nbd-server</command> will automatically switch to
-           readonly if it cannot write to the file.
-         </para>
-         <para>Does not have a corresponding command-line
-           argument</para>
-         <para>TODO: verify whether this option actually works as
-           documented. I have a feeling I've been terribly
-           stupid.
-         </para>
-       </listitem>
-      </varlistentry>
-      <varlistentry>
        <term><option>copyonwrite</option></term>
        <listitem>
          <para>
@@ -343,7 +326,24 @@ manpage.1: manpage.sgml
            then <command>nbd-server</command> will exit with an error
            message.
          </para>
-       </listitem
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><option>sync</option></term>
+       <listitem>
+         <para>Optional; boolean.</para>
+         <para>When this option is enabled,
+           <command>nbd-server</command> will call an fsync() after every
+           write to the backend storage. Calling fsync() increases
+           reliability in case of an unclean shutdown of nbd-server; but,
+           depending on the file system used on the nbd-server side, may
+           degrade performance. The use of this option isn't always
+           necessary; e.g., on ext3 filesystems, it is recommended that
+           it is <emphasis>not</emphasis> enabled, since it seriously
+           reduces performance on ext3 filesystems while not
+           importantly impacting performance.
+         </para>
+       </listitem>
       </varlistentry>
       <varlistentry>
        <term><option>sparse_cow</option></term>