man: document the random delay of persistent timers

The manual states that a persistent timer triggers it's service
immediately on activation to catch up with missed invocations, but since
PR #11608 it is no longer the case if RandomizedDelaySec= is set to a
non-zero value.

diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml
index 582240271284781312d0ed98c6674f9da8e04d77..32ddb1c6e4753977e87e92623658a2814ccad4b3 100644 (file)
--- a/man/systemd.timer.xml
+++ b/man/systemd.timer.xml
@@ -297,9 +297,10 @@
 
         <listitem><para>Takes a boolean argument. If true, the time when the service unit was last triggered
         is stored on disk.  When the timer is activated, the service unit is triggered immediately if it
-        would have been triggered at least once during the time when the timer was inactive. This is useful
-        to catch up on missed runs of the service when the system was powered down. Note that this setting
-        only has an effect on timers configured with <varname>OnCalendar=</varname>. Defaults to
+        would have been triggered at least once during the time when the timer was inactive. Such triggering
+        is nonetheless subject to the delay imposed by <varname>RandomizedDelaySec=</varname>.
+        This is useful to catch up on missed runs of the service when the system was powered down. Note that
+        this setting only has an effect on timers configured with <varname>OnCalendar=</varname>. Defaults to
         <varname>false</varname>.</para>
 
         <para>Use <command>systemctl clean --what=state …</command> on the timer unit to remove the timestamp