[rabbitmq-discuss] 3.0.4 extremely unstable in production...?

[Matt Wise]

Interesting... We are still running one node in us-west-1a, and one in us-west-1c. Today alone we saw 3 network glitches on the node in us-west-1a where it became unable to connect to remote services in other datacenters. Obviously the hardware or rack that machine is living on is having problems.

The interesting part though is that RabbitMQ did not seem to report a network partition during these events now that we're running 2.8.5 and only two nodes instead of three. I'm still digging through the logs to see if there were other interruptions, but it still feels like the code is either:
  a) more stable with 2 nodes
  b) more fault-tolerant in 2.8.5 than it is in 3.0.4

--Matt


On Apr 15, 2013, at 2:38 AM, Simon MacMullen <simon at rabbitmq.com> wrote:

> To add to what Emile said: the only difference between partition handling in 2.x and 3.x is that 3.x will show a big red warning in management when one has occurred whereas 2.x will stay silent. If you still have logs from the 2.x days you might want to grep for "running_partitioned_network" - I suspect you will find some matches.
> 
> The next release, 3.1 will have some features around automatic healing of network partitions.
> 
> Cheers, Simon
> 
> On 15/04/2013 10:16, Emile Joubert wrote:
>> 
>> Hi,
>> 
>> On 12/04/13 19:36, Matt Wise wrote:
>>> Since creating the new server farm though we've had 3 outages. In the
>>> first two outages we received a Network Partition Split, and effectively
>>> all 3 of the systems decided to run their own queues independently of
>>> the other servers. This was the first time we'd ever seen this failure,
>>> ever. In the most recent failure we had 2 machines split off, and the
>>> 3rd rabbitmq service effectively became unresponsive entirely.
>> 
>> Versions 2.8.x and 3.0.x are equally susceptible to partitions. You can
>> confirm this experimentally by setting up a cluster of v2.8.x nodes and
>> interrupting connectivity for twice the net_ticktime (60s by default).
>> 
>> See https://www.rabbitmq.com/partitions.html
>> 
>>> Up until recently though I had felt extremely comfortable with
>>> RabbitMQ's clustering technology and reliability... now ... not so much.
>>> Has anyone else seen similar behaviors? Is it simply due to the fact
>>> that we're running cross-zone now in Amazon, or is it more likely the 3
>>> servers that caused the problem? Or the 3.0.x upgrade?
>> 
>> A network outage coincided with the period when nodes were running
>> v3.0.4. The network interruption is the cause of the partition rather
>> than the broker version.
>> 
>> At the time of writing RabbitMQ clustering does not tolerate network
>> partitions well, so it should not be used over a WAN. The shovel or
>> federation plugins are better solutions for that case.
>> 
>> See http://www.rabbitmq.com/clustering.html
>> 
>> 
>> 
>> -Emile
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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>