NATS is fast and lightweight and places a priority on performance. NATS provides tools for measuring performance. In this tutorial you learn how to benchmark and tune NATS on your systems and environment.
Start the NATS server with monitoring enabled
% gnatsd -m 8222
Verify that the NATS server starts successfully, as well as the HTTP monitor:
 2016/10/31 13:26:32.037819 [INF] Starting nats-server version 0.9.4  2016/10/31 13:26:32.037912 [INF] Starting http monitor on 0.0.0.0:8222  2016/10/31 13:26:32.037997 [INF] Listening for client connections on 0.0.0.0:4222  2016/10/31 13:26:32.038020 [INF] Server is ready
Installing and running the benchmark utility
The NATS benchmark can be installed and run via Go. Ensure your golang environment is setup.
There are two approaches; you can either install the
nats-bench utility in the directory specified in your
GOBIN environment variable:
% go install $GOPATH/src/github.com/nats-io/go-nats/examples/nats-bench.go
… or you can simply run it via
% go run $GOPATH/src/github.com/nats-io/go-nats/examples/nats-bench.go
On windows use the % environment variable syntax, replacing
For the purpose of this tutorial, we’ll assume that you chose the first option, and that you’ve added the
GOBIN environment variable to your
nats-bench utility is straightforward to use. The options are as follows:
% nats-bench -h Usage: nats-bench [-s server (nats://localhost:4222)] [--tls] [-np NUM_PUBLISHERS] [-ns NUM_SUBSCRIBERS] [-n NUM_MSGS] [-ms MESSAGE_SIZE] [-csv csvfile] <subject>
The options are self-explanatory. Each publisher or subscriber runs in its own go routine with its own NATS connection.
Run a publisher throughput test
Let’s run a test to see how fast a single publisher can publish one million 16 byte messages to the NATS server.
% nats-bench -np 1 -n 100000 -ms 16 foo
The output tells you the number of messages and the number of payload bytes that the client was able to publish per second:
Starting benchmark [msgs=100000, msgsize=16, pubs=1, subs=0] Pub stats: 7,055,644 msgs/sec ~ 107.66 MB/sec
Now increase the number of messages published:
% nats-bench -np 1 -n 10000000 -ms 16 foo Starting benchmark [msgs=10000000, msgsize=16, pubs=1, subs=0] Pub stats: 7,671,570 msgs/sec ~ 117.06 MB/sec
Run a publish/subscribe throughput test
When using both publishers and subscribers,
nats-bench reports aggregate, as well as individual publish and subscribe throughput performance.
Let’s look at throughput for a single publisher with a single subscriber:
% nats-bench -np 1 -ns 1 -n 100000 -ms 16 foo
Note that the output shows the aggregate throughput as well as the individual publisher and subscriber performance:
Starting benchmark [msgs=100000, msgsize=16, pubs=1, subs=1] NATS Pub/Sub stats: 2,009,230 msgs/sec ~ 30.66 MB/sec Pub stats: 1,076,537 msgs/sec ~ 16.43 MB/sec Sub stats: 1,004,615 msgs/sec ~ 15.33 MB/sec
Run a 1:N throughput test
When specifying multiple publishers, or multiple subscribers,
nats-bench will also report statistics for each publisher and subscriber individually, along with min/max/avg and standard deviation.
Let’s increase both the number of messages, and the number of subscribers.:
% nats-bench -np 1 -ns 5 -n 10000000 -ms 16 foo
Starting benchmark [msgs=10000000, msgsize=16, pubs=1, subs=5] NATS Pub/Sub stats: 5,730,851 msgs/sec ~ 87.45 MB/sec Pub stats: 955,279 msgs/sec ~ 14.58 MB/sec Sub stats: 4,775,709 msgs/sec ~ 72.87 MB/sec  955,157 msgs/sec ~ 14.57 MB/sec (10000000 msgs)  955,150 msgs/sec ~ 14.57 MB/sec (10000000 msgs)  955,157 msgs/sec ~ 14.57 MB/sec (10000000 msgs)  955,156 msgs/sec ~ 14.57 MB/sec (10000000 msgs)  955,153 msgs/sec ~ 14.57 MB/sec (10000000 msgs) min 955,150 | avg 955,154 | max 955,157 | stddev 2 msgs
Run a N:M throughput test
When more than 1 publisher is specified,
nats-bench evenly distributes the total number of messages (
-n) across the number of publishers (
Now let’s increase the number of publishers and examine the output:
% nats-bench -np 5 -ns 5 -n 10000000 -ms 16 foo
Starting benchmark [msgs=10000000, msgsize=16, pubs=5, subs=5] NATS Pub/Sub stats: 6,716,465 msgs/sec ~ 102.49 MB/sec Pub stats: 1,119,653 msgs/sec ~ 17.08 MB/sec  226,395 msgs/sec ~ 3.45 MB/sec (2000000 msgs)  225,955 msgs/sec ~ 3.45 MB/sec (2000000 msgs)  225,889 msgs/sec ~ 3.45 MB/sec (2000000 msgs)  224,552 msgs/sec ~ 3.43 MB/sec (2000000 msgs)  223,933 msgs/sec ~ 3.42 MB/sec (2000000 msgs) min 223,933 | avg 225,344 | max 226,395 | stddev 937 msgs Sub stats: 5,597,054 msgs/sec ~ 85.40 MB/sec  1,119,461 msgs/sec ~ 17.08 MB/sec (10000000 msgs)  1,119,466 msgs/sec ~ 17.08 MB/sec (10000000 msgs)  1,119,444 msgs/sec ~ 17.08 MB/sec (10000000 msgs)  1,119,444 msgs/sec ~ 17.08 MB/sec (10000000 msgs)  1,119,430 msgs/sec ~ 17.08 MB/sec (10000000 msgs) min 1,119,430 | avg 1,119,449 | max 1,119,466 | stddev 12 msgs