Hi, I really need your help in this matter. I will try to simplify my problem and ask specific questions
I am thinking of solving the multi-tenancy problem by providing a separate cluster per each tenant. Does it sound reasonable? I can end-up with one node belongs to several clusters. Does Cassandra support several clusters per node? Does it mean several Cassandra daemons on each node? Do you recommend doing that ? what is the overhead? is there any link that explain how to do that? Thanks a lot, Mimi On Wed, Feb 16, 2011 at 6:43 PM, Mimi Aluminium <mimi.alumin...@gmail.com>wrote: > Hi, > We are interested in a multi-tenancy environment, that may consist of up to > hundreds of data centers. The current design requires cross rack and cross > DC replication. Specifically, the per-tenant CFs will be replicated 6 times: > in three racks, with 2 copies inside a rack, the racks will be located in > at least two different DCs. In the future other replication policies will be > considered. The application will decide where (which racks and DC) to place > each tenant's replicas. and it might be that one rack can hold more than > one tenant. > > Separating each tenant in a different keyspace, as was suggested > in previous mail thread in this subject, seems to be a good approach > (assuming the memtable problem will be solved somehow). > But then we had concern with regard to the cluster size. > and here are my questions: > 1) Given the above, should I define one Cassandra cluster that hold all the > DCs? sounds not reasonable given hundreds DCs tens of servers in each DC > etc. Where is the bottleneck here? keep-alive messages, the gossip, request > routing? what is the largest number of servers a cluster can bear? > 2) Now assuming that I can create the per-tenant keyspace only for the > servers that in the three racks where the replicas are held, does such > definition reduces the messaging transfer among the other servers. Does > Cassandra optimizes the message transfer in such case? > 3) Additional possible solution was to create a separate clusters per each > tenant. But it can cause a situation where one server has to run two or more > Cassandra's clusters. Can we run more than one cluster in parallel, does it > means two cassandra daemons / instances on one server? what will be the > overhead? do you have a link that explains how to deal with it? > > Please can you help me to decide which of these solution can work or you > are welcome to suggest something else. > Thanks a lot, > Mimi > > > > > > > >
