On 10/28/2011 10:12 PM, Daryoush Mehrtash wrote:
I have a distributed QPID broker scenario that need to make sure messages
are received at-least-once in the remote clients. I am trying to see if I
have to configure the brokers or not.
On the source broker I have:
qpid-config -a SRC_BROKER add queue SRC_QUEUE
On Destination broker I set up the route and queues to read from
qpid-route queue add DEST_BROKER SRC_BROKER amq.fanout SRC_QUEUE
You probably want to add in --ack N to the qpid-route command. That will
make transfer acknoweldeged, giving at-least-once guarantees between
brokers.
[The N determines the frequency of acknowledgements; i.e. an
acknowledgement will be sent every N messages. Lower values will reduce
the size of the in-doubt window, higher values (up to a point, say
around 200 or so) will generally increase throughput of the link.]
qpid-config -a DEST_BROKER add queue DEST_QUEUE
qpid-config -a DEST_BROKER bind amq.fanout DEST_QUEUE
I like to run the spout and drain apps in the python example.
spout SRC_QUEUE
drain "DEST_QUEUE; {link:{reliability:"at-least-once"}}"
Questions:
a) Do I have to do anything on the "spout" to make sure the message has
at-least-once reliability>
It depends on what types of failure you wish the guarantee to survive
for. If you want durability (i.e. the ability to recover messages if
either broker is restarted) then the messages should be sent as
persistent (and all queues they pass through should be made durable).
The spout example does not at present have a command line option for
setting persistence but that is easy to add.
Apart from that you want to specify --reconnect to have it attempt to
re-establish connection to the broker if lost and re-send any in-doubt
messages.
For the queues you would add --durable to the qpid-config command for
SRC_QUEUE and durable:True alongside the reliability option in your
drain address.
[You also need to have the store plugin loaded].
b) Do I have to configure the Destination borker, or the route to make sure
all messages are sent to the broker.
Make sure you have acknowldeged transfer enabled between brokers and
reconnect enabled on your publisher (spout in this case).
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