[rabbitmq-discuss] Confusing disk free space limit warning

[Mark Hingston]

On 18/09/12 3:46 PM, Matthias Radestock wrote:

>>> So your question really comes down to how would you expect a client to
>>> detect and deal with a slow server / congested network.
>>
>> Thanks for the explanation. I guess now I'm trying to figure out what
>> the best way is to defend against this situation so that my messages
>> don't get lost.
>
> As you noted, publisher confirms would be one way and are definitely 
> the way to go when wanting to ensure that no messages are lost, ever, 
> on their delivery to rabbit. I don't know about their status in celery.
>
> However, before you go down that route, consider carefully what other 
> failure modes there are in your system. It's all very well to ensure 
> that the message delivery to rabbit is reliable, but if the connecting 
> application can explode and lose messages then that may not actually 
> gain you very much.
>
> On the rabbit/connection side, messages will only be lost if the 
> connection is dropped or rabbit encounters some catastrophic internal 
> error. Alarm conditions are transitory, i.e. you can recover from them 
> w/o restarting rabbit, by, say, consuming messages (to free up memory) 
> or clearing some disk space.
>
> So depending on how reliable your network and machines are (and 
> leaving aside the alarm-handler-killing stomp bug), the most likely 
> place for messages to get dropped may not actually be on the rabbit side.

Thanks for that - I'll keep it in mind. I've raised the question of how 
best to handle this situation when running celery in this thread over at 
the celery group:

https://groups.google.com/forum/#!msg/celery-users/G-tq8SsHkuA/01Ndr2VBZhwJ