Hi Christian, thanks a lot. Yes I talked about eLevelDB (forgot to write it into the mail). This helps me a lot. I already thought to use 256 as ringsize but wasn't 100% sure.
Cheers, Simon On Mon, 28 Jan 2013 17:23:56 +0000 Christian Dahlqvist <[email protected]> wrote: > Hi Simon, > > By cache size, I am assuming you are referring to the leveldb internal cache. > Is this correct? > > The arguably most important parameter in your configuration is the ring size. > Defining an appropriate ring size is very important as it can't change later > on and determines how far you can scale. It is recommended that you allow for > at about 10 partitions per physical node > (http://docs.basho.com/riak/1.3.0/references/appendices/Cluster-Capacity-Planning/#Ring-Size-Number-of-Partitions), > which means that if you are preparing for a cluster of around 20 nodes, you > should probably use 256 partitions. > > At the moment we do not recommend tuning the eleveldb cache_size at all, so > it would be best to leave it at the default value. > > With an n_val of 3, Riak will store every record on 3 consecutive vnodes in > the ring. The case where multiple copies may end up on less than 3 different > physical servers primarily applies to cases where there are less than 4 nodes > in the cluster as nodes will repeat around the ring wrap around point.This is > one of the reasons we recommend using at least 5 nodes in the cluster. > > Best regards, > > Christian > > > On 28 Jan 2013, at 15:47, "Effenberg, Simon" <[email protected]> > wrote: > > > Hi, > > > > we want to save plenty of mails in riak which are in average 14k big. Our > > cluster will become between 10 to 20 nodes so the question is: what is > > better, having more partitions but each has less cache or is it the other > > way around so having less partitions with more cache size? > > > > Also with an n_val of 3 it is always said, that there is no guarantee for > > having this on 3 physical nodes but also that it should be distributed > > evenly. What does it mean? Is there any calculation I can do to get a > > feeling how often 3 replicas are only on 2 nodes? Or can you say: with 6 > > nodes and an n_val of 3 it should be the case that almost 99.9 percent is > > distributed over different physical nodes? > > > > Cheers, > > Simon > > _______________________________________________ > > riak-users mailing list > > [email protected] > > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > -- Simon Effenberg | Site Ops Engineer | mobile.international GmbH Fon: + 49-(0)30-8109 - 7173 Fax: + 49-(0)30-8109 - 7131 Mail: [email protected] Web: www.mobile.de Marktplatz 1 | 14532 Europarc Dreilinden | Germany Geschäftsführer: Malte Krüger HRB Nr.: 18517 P, Amtsgericht Potsdam Sitz der Gesellschaft: Kleinmachnow _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
