<Plugin write_tsdb>
DNS_Cache_TTL 60
+ DNS_Random_Cache_TTL 60
<Node "example">
Host "tsd-1.my.domain"
Port "4242"
=item B<DNS_Cache_TTL> I<ttl>
+=item B<DNS_Random_Cache_TTL> I<ttl>
+
When Collectd connects to a TSDB node, it will request the DNS. This can become
a problem is the TSDN node is unavailable or badly configured because Collected
will request DNS in order to reconnect for every metric, which can flood your DNS.
-So you can cache the last value for C<ttl> seconds (default: 60s).
+So you can cache the last value for C<ttl> seconds (default: 600s e.g; 10 min).
+
+You can also define a random ttl. This prevents all your Collectd servers to
+request the DNS at the same time when the connection fails. Default value is
+15 * the write_tsdb interval (or the global interval if write_tsdb interval is not
+defined).
+
+Note : if the DNS resolution has already been successful, if the socket closes,
+the plugin will try to reconnect as soon as possible with the cached information.
+DNS is queried only when the socket is closed for a long time (DNS_Cache_TTL +
+DNS_Random_Cache_TTL)
=back