Hi Quan,
thanks for your reply!
Good to know that I misunderstood the dequeuing in the code and it actually
works like I would like.
Do you know for which queues ActiveMQ and for which RabbitMQ is used?
Do I have to configure a dedicated RabbitMQ server for persistence? My
deployment currently uses an in-memory RabbitMQ which does not have
persistence, I guess.
Is there documentation anywhere on how to configure the queues for persistence?
Best regards,
Felix
On 16/09/2026 11.30, Quan tran hong wrote:
Hi Felix,
If I understand the James code correctly (please correct me if I'm
wrong), the processors completely take emails out of the queue (meaning
they only exist in memory?) and reinsert them later if necessary.
This would mean that a crash / server restart while an email is processed
would mean that the email is lost with no possibility of informing the
client. Can I do something about that?
Dequeueing does not permanently remove a mail from the mail queue (yet).
James keeps it unacknowledged while processing it and commits/acknowledges
it; failures cause rollback/nack and redelivery by RabbitMQ. A James
restart during processing, therefore, would not cause message loss.
Can I configure persistence for the email queues? I would like to have a
system which I can restart while emails are queued without them getting
lost.
I think for RabbitMQ, James set those mail queues to be *durable* already.
You just need to make sure your RabbitMQ data path is persisted (in case
you use Docker).
I hope it helps.
Regards,
Quan
On Wed, Sep 16, 2026 at 1:54 PM Felix Auringer <[email protected]>
wrote:
Hello together,
I have some questions regarding the email queues in James.
As far as I understand, there are two processes where an email queue is
necessary, receiving email and sending email.
In my head, the ideal process for these processes looks like this:
- After the client has sent all commands, the email is put in a queue
(spool / outgoing).
- If and only if the queue operation succeeded, James tells the client
that its email was received successfully.
- The spooler/deliverer takes an email from the queue and processes it
(mailetcontainer / remote delivery).
- If and only if the email processing was successful (persisted in
mailbox/accepted by remote server), the email is removed from the queue.
If I understand the James code correctly (please correct me if I'm wrong),
the processors completely take emails out of the queue (meaning they only
exist in memory?) and reinsert them later if necessary.
This would mean that a crash / server restart while an email is processed
would mean that the email is lost with no possibility of informing the
client. Can I do something about that?
According to the docs (and logs during startup), James uses two different
message queues:
- ActiveMQ (https://james.apache.org/server/config-activemq.html):
Manages at least the queues 'spool' and 'outgoing' according to the docs.
According to my logs, it uses KahaDB as persistence adapter.
- RabbitMQ (https://james.apache.org/server/config-rabbitmq.html): Used
for distributed MailQueue and distributed event system according to the
docs. It is also running in my single node deployment (as in-memory version
because I did not configure anything).
Which of them is used for the processes described above?
Can I configure persistence for the email queues? I would like to have a
system which I can restart while emails are queued without them getting
lost.
Best regards,
Felix
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Felix Auringer
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Gesellschaft für interkulturelles
Zusammenleben gGmbH (GIZ)
Felix Auringer
IT
Reformationsplatz 2
13597 Berlin
Tel: 030/513 0100 00; Fax: 030/513 0100 09
www.giz.berlin; [email protected]
Amtsgericht Charlottenburg HRB 200872 B
Geschäftsführerin: Dr. Britta Marschke
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