[rabbitmq-discuss] memory usage reporting

[Simon MacMullen]

Hmm. I am curious. On my machine (Ubuntu 10.04) the amount of memory 
reported used in "rabbitmqctl status" matches up much more closely with 
RES than with VIRT (which is roughly what you'd expect).

In your case the 17.9GB VIRT vs 269MB RES is too much to be explained by 
paged-out memory since you have 5GB of swap that is not used). So I 
would expect it to be memory-mapped files or other mysterious things.

However, Erlang certainly thinks that your RabbitMQ process is really 
using 15.5GB of memory; the memory breakdown looks plausible and those 
numbers do not at all correspond to memory-mapped files or whatever.

So I am not surprised the memory alarm has gone off, what surprises me 
is that the OS is reporting so little real memory in use. Which OS is 
it? How did you install Erlang?

Cheers, Simon

On 24/04/13 14:49, Kyle O'Donnell wrote:
> Hi,
>
> I've built rabbit (2.8.7 and 3.0.4) from source using R15B03, here
> are the build time options:
>
> make RABBITMQ_BASE=/x/s/rabbitmq-server-3.0.4
> RABBITMQ_LOG_BASE=/x/s/rabbitmq-server-3.0.4/var/log
> RABBITMQ_CONFIG_FILE=/x/s/rabbitmq-server-3.0.4/etc/rabbitmq
> RABBITMQ_MNESIA_DIR=/x/s/rabbitmq-server-3.0.4/var/lib/mnesia
> TARGET_DIR=/x/s/rabbitmq-server-3.0.4
> SBIN_DIR=/x/s/rabbitmq-server-3.0.4/sbin
> MAN_DIR=/x/s/rabbitmq-server-3.0.4/man
>
> When I start my app rabbit quickly reports that it's reached the high
> watermark for memory usage, and it counts virtual memory not resident
> memory:
>
> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+ COMMAND
> 29723 prod      20   0 17.9g 269m 2752 S    4  0.8   2:40.80
> /x/s/erlang-R15B03/lib/erlang/erts-5.9.3.1/bin/beam.smp -W w -K true
> -A30 -P 1048576 -- -root /x/s/erlang-R15B03/lib/erlang -progname erl
> -- -home /home/prod -- -pa /x/s/rabbitmq
>
> There is plenty of free memory on the machine
>
> $ free -m total       used       free     shared    buffers
> cached Mem:         32178       2992      29186          0        242
> 1929 -/+ buffers/cache:        820      31358 Swap:         5719
> 0       5719
>
> Is this normal? Curious why rabbit cares about the virtual memory
> size when there is so much actual memory available.
>
> below is the output from rabbitmqctl status
>
> Thanks, Kyle
>
>
> rabbitmqctl status Status of node 'rabbit at p1-amqp-j101' ...
> [{pid,29723}, {running_applications,
> [{rabbitmq_management_visualiser,"RabbitMQ Visualiser","0.0.0"},
> {rabbitmq_management,"RabbitMQ Management Console","0.0.0"},
> {rabbitmq_management_agent,"RabbitMQ Management Agent","0.0.0"},
> {rabbit,"RabbitMQ","3.0.4"}, {mnesia,"MNESIA  CXC 138 12","4.7.1"},
> {os_mon,"CPO  CXC 138 46","2.2.10"}, {rabbitmq_web_dispatch,"RabbitMQ
> Web Dispatcher","0.0.0"},
> {webmachine,"webmachine","1.9.1-rmq0.0.0-git52e62bc"},
> {mochiweb,"MochiMedia Web Server","2.3.1-rmq0.0.0-gitd541e9a"},
> {xmerl,"XML parser","1.3.2"}, {inets,"INETS  CXC 138 49","5.9.2"},
> {amqp_client,"RabbitMQ AMQP Client","0.0.0"}, {sasl,"SASL  CXC 138
> 11","2.2.1"}, {stdlib,"ERTS  CXC 138 10","1.18.3"}, {kernel,"ERTS
> CXC 138 10","2.15.3"}]}, {os,{unix,linux}}, {erlang_version, "Erlang
> R15B03 (erts-5.9.3.1) [source] [64-bit] [smp:4:4] [async-threads:30]
> [hipe] [kernel-poll:true]\n"}, {memory, [{total,15536914264},
> {connection_procs,89537888}, {queue_procs,18333416},
> {plugins,1170400}, {other_proc,6548309}, {mnesia,2538168},
> {mgmt_db,32239752}, {msg_index,615120}, {other_ets,3557064},
> {binary,15276878352}, {code,20248995}, {atom,801697},
> {other_system,84445103}]}, {vm_memory_high_watermark,0.4},
> {vm_memory_limit,13496687001}, {disk_free_limit,1000000000},
> {disk_free,22007357440}, {file_descriptors, [{total_limit,130970},
> {total_used,1828}, {sockets_limit,117871}, {sockets_used,1826}]},
> {processes,[{limit,1048576},{used,20875}]}, {run_queue,0},
> {uptime,1620}] ...done.
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-- 
Simon MacMullen
RabbitMQ, VMware