Hi Alex, You seem to be referring to bitcask metadata. That metadata is loaded into ram on each node. As you note, the bitcask capacity planner calculates ram required by a cluster to service a certain number of keys. I think where you are confused is that this metadata is not synced across the cluster. It is specific to the data stored specifically on each node.
-Alexander Alexander Sicular Solutions Architect Basho Technologies 9175130679 @siculars On Fri, Jan 6, 2017 at 11:31 AM, Alex Feng <sweden.f...@gmail.com> wrote: > > Hi Riak Users, > > I am a little bit confused about the metadata, it is stored in memory and > synced in every node, so bascially every node share the same metadata, > right ? > But then from the official document, the formula to calcuate the RAM > requirement, the RAM requirement is for whole cluster, for example, based > on the formula below, the requirement is 50G, then if we have 5 nodes, then > each node only needs 10G RAM. Seems the metadata is divided to different > nodes, I must hvae misunderstood something, could someone please to clarify > this, thank you very much. > > > https://docs.basho.com/riak/kv/2.2.0/setup/planning/bitcask-capacity-calc/ > > Approximate RAM Needed for Bitcask = (static bitcask per key overhead + > estimated average bucket+key length in bytes) * estimate total number of > keys * n_val > > > > Br, > Alex > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > >
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