Here's how you can increase the length of a session in Subsonic from the default of 30 minutes to something longer. In this example I'm increasing it to 2 weeks (20160 minutes).
mkdir workspace
cd workspace
sudo cp /usr/share/subsonic/subsonic-booter-jar-with-dependencies.jar /usr/share/subsonic/subsonic-booter-jar-with-dependencies.jar.orig
unzip /usr/share/subsonic/subsonic-booter-jar-with-dependencies.jar
cat > webdefault.patch <<End-of-message
--- org/mortbay/jetty/webapp/webdefault.xml.orig 2014-06-11 10:06:12.000000000 -0700
+++ org/mortbay/jetty/webapp/webdefault.xml 2014-06-11 10:06:39.000000000 -0700
@@ -323,7 +323,7 @@
<!-- ==================================================================== -->
<session-config>
- <session-timeout>30</session-timeout>
+ <session-timeout>20160</session-timeout>
</session-config>
<!-- ==================================================================== -->
End-of-message
patch -p0 webdefault.patch && rm webdefault.patch
sudo service subsonic stop
sudo zip -r /usr/share/subsonic/subsonic-booter-jar-with-dependencies.jar ./
sudo service subsonic start