Recommended riak configuration options for better performance

Alex Moore amoore at basho.com
Thu Jun 5 09:44:53 EDT 2014


Hi Naveen,

You are running out of MR workers, you’ll either have to:
a) Increase the worker limits on the current nodes (particularly map_js_vm_count and reduce_js_vm_count)
b) Add more nodes (and thereby more workers)
c) Do less MR work.
d) Implement your MapReduce functions in Erlang to avoid the JS VM altogether

Bryan Fink has a nice writeup on how to estimate your MR worker needs here: 
http://riak-users.197444.n3.nabble.com/Follow-up-Riak-Map-Reduce-error-preflist-exhausted-tp4024330p4024380.html

Thanks,
Alex

On Jun 4, 2014, at 7:58 AM, Naveen Tamanam <naveen32india at gmail.com> wrote:

> Hi Guys, 
> 
> 
> I have 5 nodes riak cluster in  use. Each machine is having 16GB ram.  All those 5 machines are 
> ​dedicated for riak only. No other application is there to eat resources. ​ ​I use to do a lot of work with
> map reduce queries. Having a may map reduce queries with both map and reduce phases. 
> I have many cases with the  the following error and log messages, ​
>>                           "error":"[preflist_exhausted]"
>                          RiakError: 'could not get a response'   
>                          All VMs are busy
> 
> I know  above errors can be avoided with fine tuned riak configuration options. I am looking for recommended values
> Here  are  few riak configuration options currently I have on each node, 
> 
>               { kernel, [
>             {inet_dist_listen_min, 6000},
>             {inet_dist_listen_max, 7999}
>           ]},
> 
>                {map_js_vm_count, 48 },
>                {reduce_js_vm_count, 26 },
>                {hook_js_vm_count, 12 },
>                 {js_max_vm_mem, 32},
>                  {js_thread_stack, 16}
>                
> 
> 
>                          
> 
> 
> 
> 
> 
>> -- 
> Thanks & Regards,
> Naveen Tamanam ​​
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> riak-users mailing list
> riak-users at lists.basho.com
> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com

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