the optimal value of the ring_creation_size

Joe Caswell jcaswell at basho.com
Mon Apr 22 17:17:07 EDT 2013


Tom,
  There is no hard and fast rule for the "best value."  The optimal value
for your situation will need to take into account the physical resources
available both in your starting cluster as well as your planned end-state
cluster.  If you plan to use secondary indexing, the maximum
ring_creation_size you should consider is 512.
  There will be a separate concurrent vnode_proxy process for each vnode,
and a process for each backend for each vnode.  Each backend will need open
file handles and RAM for caching objects.  The backend configuration section
of the docs should help plan your backed settings
http://docs.basho.com/riak/1.3.1/tutorials/choosing-a-backend/
  Your planning must also include failure scenarios.  If any of your nodes
crash, the surviving nodes will each start more vnodes to cover the missing
node(s).   The 10 vnodes per node recommendation is to ensure that the
vnodes from any single failed node can be divided among enough surviving
nodes to not leave one node handling significantly more load than the other,
but this also is not a hard and fast rule.
At this time changing number of partitions in the ring does require a
complete rebuild of the cluster,  we do have dynamic ring sizing on the
product roadmap, but there is no release date set for that feature.

Joe Caswell

From:  Tom Zeng <tom at intridea.com>
Date:  Sunday, April 21, 2013 9:38 PM
To:  <riak-users at lists.basho.com>
Subject:  the optimal value of the ring_creation_size

Hi,

I am wondering what's the best value for ring_creation_size, the default is
64. According to the docs 64 will work for a cluster of no more than 6 nodes
(64 /10), and ring_creation_size of 128 will allow cluster of up to 12 mode.
I am wondering what kind of overhead of is associated with a large
ring_creation_size.  Since changing the ring_creation_size will result in
rebuilding the cluster(destuctive), would a larger value make more sense and
allow scaling by adding more nodes?


Thanks,
Tom

-- 
Tom Zeng
Director of Engineering
Intridea, Inc. | www.intridea.com <http://www.intridea.com>
tom at intridea.com
(o) 888.968.4332 x519
(c) 240-643-8728
_______________________________________________ riak-users mailing list
riak-users at lists.basho.com
http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.basho.com/pipermail/riak-users_lists.basho.com/attachments/20130422/6f038b69/attachment.html>


More information about the riak-users mailing list