big cache vs. many partitions and replicas placement

Effenberg, Simon seffenberg at team.mobile.de
Mon Jan 28 10:47:22 EST 2013


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


More information about the riak-users mailing list