diff --git a/manifests/server.pp b/manifests/server.pp
index 20eae98..3db3e0a 100644
--- a/manifests/server.pp
+++ b/manifests/server.pp
@@ -63,7 +63,10 @@
   $inputbuffer_ring_size                              = $graylog2::server::params::inputbuffer_ring_size,
   $inputbuffer_wait_strategy                          = $graylog2::server::params::inputbuffer_wait_strategy,
   $is_master                                          = $graylog2::server::params::is_master,
+  $max_heap                                           = "${graylog2::server::params::max_heap}m",
+  $perm_size                                          = "${graylog2::server::params::perm_size}m",
   $java_opts                                          = $graylog2::server::params::java_opts,
+  $java_opts_extra                                    = $graylog2::server::params::java_opts_extra,
   $lb_recognition_period_seconds                      = $graylog2::server::params::lb_recognition_period_seconds,
   $ldap_connection_timeout                            = $graylog2::server::params::ldap_connection_timeout,
   $message_journal_dir                                = $graylog2::server::params::message_journal_dir,
@@ -206,7 +209,10 @@
     inputbuffer_ring_size                              => $inputbuffer_ring_size,
     inputbuffer_wait_strategy                          => $inputbuffer_wait_strategy,
     is_master                                          => $is_master,
+    max_heap                                           => $max_heap,
+    perm_size                                          => $perm_size,
     java_opts                                          => $java_opts,
+    java_opts_extra                                    => $java_opts_extra,
     lb_recognition_period_seconds                      => $lb_recognition_period_seconds,
     ldap_connection_timeout                            => $ldap_connection_timeout,
     message_journal_dir                                => $message_journal_dir,
diff --git a/manifests/server/configure.pp b/manifests/server/configure.pp
index 3f72ae3..51b555f 100644
--- a/manifests/server/configure.pp
+++ b/manifests/server/configure.pp
@@ -60,7 +60,10 @@
   $inputbuffer_ring_size,
   $inputbuffer_wait_strategy,
   $is_master,
+  $max_heap,
+  $perm_size,
   $java_opts,
+  $java_opts_extra,
   $lb_recognition_period_seconds,
   $ldap_connection_timeout,
   $message_journal_dir,
diff --git a/manifests/server/params.pp b/manifests/server/params.pp
index 76b00f6..42d56cc 100644
--- a/manifests/server/params.pp
+++ b/manifests/server/params.pp
@@ -79,7 +79,10 @@
   $inputbuffer_ring_size = '65536'
   $inputbuffer_wait_strategy = 'blocking'
   $is_master = true
-  $java_opts = '-Xms1g -Xmx1g -XX:NewRatio=1 -XX:PermSize=128m -XX:MaxPermSize=256m -server -XX:+ResizeTLAB -XX:+UseConcMarkSweepGC -XX:+CMSConcurrentMTEnabled -XX:+CMSClassUnloadingEnabled -XX:+UseParNewGC -XX:-OmitStackTraceInFastThrow'
+  $max_heap =  clamp(1024, $::memorysize_mb / 2, 32000)
+  $perm_size = clamp(256, $max_heap / 20, 1024)
+  $java_opts = '-server -XX:+ResizeTLAB -XX:+UseConcMarkSweepGC -XX:+CMSConcurrentMTEnabled -XX:+CMSClassUnloadingEnabled -XX:+UseParNewGC -XX:-OmitStackTraceInFastThrow'
+  $java_opts_extra = ''
   $lb_recognition_period_seconds = '3'
   $ldap_connection_timeout = '2000'
   $message_journal_dir = '/var/lib/graylog-server/journal'
diff --git a/spec/classes/server_spec.rb b/spec/classes/server_spec.rb
index 3741be8..9c285ff 100644
--- a/spec/classes/server_spec.rb
+++ b/spec/classes/server_spec.rb
@@ -20,6 +20,7 @@
     let(:default_facts) do
       {
         :osfamily => dist,
+        :memorysize_mb => 12000,
       }
     end
 
@@ -40,7 +41,7 @@
         should contain_package('graylog-server').with_ensure('installed')
       }
       it {
-        should contain_file(defaults_path).with_content(/^GRAYLOG_SERVER_JAVA_OPTS="-Xms1g -Xmx1g -XX:NewRatio=1 -XX:PermSize=128m -XX:MaxPermSize=256m -server -XX:\+ResizeTLAB -XX:\+UseConcMarkSweepGC -XX:\+CMSConcurrentMTEnabled -XX:\+CMSClassUnloadingEnabled -XX:\+UseParNewGC -XX:-OmitStackTraceInFastThrow"/)
+        should contain_file(defaults_path).with_content(/^GRAYLOG_SERVER_JAVA_OPTS="-Xms6000m -Xmx6000m -XX:NewRatio=1 -XX:PermSize=300m -XX:MaxPermSize=300m -server -XX:\+ResizeTLAB -XX:\+UseConcMarkSweepGC -XX:\+CMSConcurrentMTEnabled -XX:\+CMSClassUnloadingEnabled -XX:\+UseParNewGC -XX:-OmitStackTraceInFastThrow"/)
       }
     end
 
@@ -60,4 +61,19 @@
     end
   end
 
+  context 'should allow to set Xms and Xmx through max_heap, and PermSize through perm_size' do
+    let(:facts) do
+      {
+      }.merge default_facts
+    end
+    let(:params) do
+      {
+        :max_heap => '3g',
+        :perm_size => '300m',
+      }.merge default_params
+    end
+    it {
+      should contain_file(defaults_path).with_content(/^GRAYLOG_SERVER_JAVA_OPTS="-Xms3g -Xmx3g -XX:NewRatio=1 -XX:PermSize=300m -XX:MaxPermSize=300m -server -XX:\+ResizeTLAB -XX:\+UseConcMarkSweepGC -XX:\+CMSConcurrentMTEnabled -XX:\+CMSClassUnloadingEnabled -XX:\+UseParNewGC -XX:-OmitStackTraceInFastThrow"/)
+    }
+  end
 end
diff --git a/templates/server.default.erb b/templates/server.default.erb
index 7727b8f..7459192 100644
--- a/templates/server.default.erb
+++ b/templates/server.default.erb
@@ -3,8 +3,14 @@
 # Path to the java executable.
 JAVA=/usr/bin/java
 
+<%- if @java_opts.include? '-Xms' -%>
 # Default Java options for heap and garbage collection.
-GRAYLOG_SERVER_JAVA_OPTS="<%= @java_opts %>"
+GRAYLOG_SERVER_JAVA_OPTS="<%= @java_opts %><%= @java_opts_extra %>"
+<%- else -%>
+# Default Java options for heap and garbage collection.
+<%- jvm_memory="-Xms#{@max_heap} -Xmx#{@max_heap} -XX:NewRatio=1 -XX:PermSize=#{@perm_size} -XX:MaxPermSize=#{@perm_size}" -%>
+GRAYLOG_SERVER_JAVA_OPTS="<%= jvm_memory %> <%= @java_opts %><%= @java_opts_extra %>"
+<%- end -%>
 
 # Pass some extra args to graylog-server. (i.e. "-d" to enable debug mode)
 GRAYLOG_SERVER_ARGS="<%= @extra_args %>"
diff --git a/templates/server.sysconfig.erb b/templates/server.sysconfig.erb
index b912ab7..431be1c 100644
--- a/templates/server.sysconfig.erb
+++ b/templates/server.sysconfig.erb
@@ -3,8 +3,14 @@
 # Path to the java executable.
 JAVA=/usr/bin/java
 
+<%- if @java_opts.include? '-Xms' -%>
 # Might be used to adjust the Java heap size. (i.e. "-Xms1024m -Xmx2048m")
-GRAYLOG_SERVER_JAVA_OPTS="<%= @java_opts %>"
+GRAYLOG_SERVER_JAVA_OPTS="<%= @java_opts %><%= @java_opts_extra %>"
+<%- else -%>
+# Might be used to adjust the Java heap size. (i.e. "-Xms1024m -Xmx2048m")
+<%- jvm_memory="-Xms#{@max_heap} -Xmx#{@max_heap} -XX:NewRatio=1 -XX:PermSize=#{@perm_size} -XX:MaxPermSize=#{@perm_size}" -%>
+GRAYLOG_SERVER_JAVA_OPTS="<%= jvm_memory %> <%= @java_opts %><%= @java_opts_extra %>"
+<%- end -%>
 
 # Pass some extra args to graylog-server. (i.e. "-d" to enable debug mode)
 GRAYLOG_SERVER_ARGS="<%= @extra_args %>"