[rabbitmq-discuss] Unable to start RabbitMQ server after crash because of vm_memory_high_watermark alarm.

Tue Aug 23 12:16:39 BST 2011

Hi Chris,

On Sun, Aug 21, 2011 at 05:08:39PM -0700, ChrisStoyles wrote:
> I need some advice on moving /var/lib/rabbitmq to a new server with
> more RAM. What has happened is that on our 8GB RAM server we've had a
> surge in activity and one of our queues has grown much faster than it
> can be consumed by our "workers".
> 
> This has resulted in RabbitMQ crashing, with an erl_crash.dump file
> appearing.
> 
> At present when I attempt to start the server up again, it tries to
> roll the persister.LOG file and recover what was in the queue at the
> time of the crash. However even with rabbitmq.config set up as below,
> the vm_memory_high_watermark alarm is triggered and erl_crash.dump is
> created all over again.

Erm, persister.LOG suggests a RabbitMQ pre 2.0.0. Is that true? We would
very strongly recommend you upgrade asap.

> [
>   {rabbit, [{vm_memory_high_watermark, 0.9}]}
> ].

Yeah, that's not going to make any difference to pre 2.0 Rabbits. Pre
2.0, all msgs are always held in RAM.

> I've got another server with 24GB of RAM, so I set it's HOSTNAME to
> the same as the 8GB server and installed the same version of RabbitMQ.
> I then copied over the contents of /var/lib/rabbitmq and attempted to
> start RabbitMQ. I no longer hit the vm_memory_high_watermark however
> Erlang seems to close/shutdown while attempting to recover
> persister.LOG.

That's odd - if the hostname and the nodename of Rabbit is the same, it
should start up I think. Is there anything in the logs?

Matthew