SV: [newbie] riak performance - basics

Jens Rantil jens.rantil at telavox.se
Wed Apr 13 10:16:20 EDT 2011


Hi M H,

The default Riak configuration has N=3 [1], which means that it is configured to run on a 3-node environment. This also means that every PUT you do must write 3 values to your local machine! Changing n_val for your Riak bucket to 1 will make more sense for a 1-node environment.

[1] http://wiki.basho.com/Replication.html#Selecting-an-N-value-(n_val)

Also, have a look at the previous thread [2] that I posted a couple of days ago. In short, the RESTful interface can be quite slow. Maybe have a look at Sean Cribbs parameter. Or event better, use the protocol buffer API instead.

[2] http://lists.basho.com/pipermail/riak-users_lists.basho.com/2011-April/003849.html

Regards,
Jens

-----Ursprungligt meddelande-----
Från: riak-users-bounces at lists.basho.com [mailto:riak-users-bounces at lists.basho.com] För M H
Skickat: den 13 april 2011 14:59
Till: riak-users at lists.basho.com
Ämne: [newbie] riak performance - basics

Hi,

I am new to Riak - just compiled it and trying it out. I have some questions about performance.

I am running a single riak node with default configuration (only changed the IPs) on a core i7 machine (Ubuntu). I run a very simple JMeter test (RESTful calls):
 1 .PUT a simple json object into riak (~30 bytes; key is static - so DB has only one key)
 2. GET the object

While the test is running riak seems to be using all the CPU it can get - 'top' reports ~99.5% CPU usage (beam.smp is using ~780% so all 8 cores).

Here are some results from the JMeter test:
* 5 threads:
 1.PUT  avg: 458 ms  Throughput 6.1/sec
 2.GET  avg: 355 ms  Throughput 6.1/sec

* 50 threads:
 1.PUT  avg: 5325 ms  Throughput 6.1/sec
 2.GET  avg: 2838 ms  Throughput 6.1/sec

The numbers are pretty disappointing. Is there something wrong with the default configuration? Or I am misusing riak in some way? There is only 1 key with simple value in the DB....


Here's some numbers from admin stats:

vnode gets : 2118
vnode_puts : 1067
read_repairs : 1
vnode_gets_total : 224061
vnode_puts_total : 89045
node_gets : 680
node_gets_total : 74676
node_get_fsm_time_mean : 3047570
node_get_fsm_time_median : 2949500
node_get_fsm_time_95 : 4888000
node_get_fsm_time_99 : 5964050
node_get_fsm_time_100 : 6348870
node_puts : 339
node_puts_total : 29543
node_put_fsm_time_mean : 2433651
node_put_fsm_time_median : 2472125
node_put_fsm_time_95 : 4054512
node_put_fsm_time_99 : 4504152
node_put_fsm_time_100 : 4908213
read_repairs_total : 180
cpu_nprocs : 620
cpu_avg1 : 2104
cpu_avg5 : 2117
cpu_avg15 : 2099
storage_backend : riak_kv_bitcask_backend

Any hints?

--
MH

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