10-15 KS should be fine. The issue is when you want to have hundreds or thousands of KS/CF.
-Jeremiah -----Original Message----- From: Subrahmanya Harve [mailto:subrahmanyaha...@gmail.com] Sent: Thursday, February 02, 2012 1:43 AM To: dev@cassandra.apache.org Subject: Re: Queries on AuthN and AuthZ for multi tenant Cassandra Thanks for the response Aaron. We do not anticipate more than 10-15 tenants on the cluster. Even if one does decide to create one KS/tenant, there is the problem of variable loads on the KS's. I went through this link http://www.datastax.com/dev/blog/whats-new-in-cassandra-1-0-improved-mem ory-and-disk-space-managementwhich does promise better memory management. I did have two more questions - - Was the new memory management written taking into account a situation of many KS's? (In other words, did multi-tenancy influence the re-design of memory management?) - i know that users trying out multi-tenancy are generally recommending not to create many Ks's/CF's, but i am wondering if there is any documentation for why this happens or the details on the negative impact on memory/performance?and are there are any performance benchmarks available for Cassandra 1.0 clusters with many KS's? On Wed, Feb 1, 2012 at 12:11 PM, aaron morton <aa...@thelastpickle.com>wrote: > The existing authentication plug-in does not support row level > authorization. > > You will need to add authentication to your API layer to ensure that a > request from client X always has the client X key prefix. Or modify > cassandra to provide row level authentication. > > The 1.x Memtable memory management is awesome, but I would still be > hesitant about creating KS's and CF's at the request of an API client. > > Cheers > > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 2/02/2012, at 8:52 AM, Subrahmanya Harve wrote: > > > We are using Cassandra 0.8.7 and building a multi-tenant cassandra > platform > > where we have a common KS and common CFs for all tenants. By using > Hector's > > virtual keyspaces, we are able to add modify rowkeys to have a tenant > > specific id. (Note that we do not allow tenants to modify/create KS/CF. > We > > just allow tenants to write and read data) However we are in the process > of > > adding authentication and authorization on top of this platform such that > > no tenant should be able to retrieve data belonging to any other tenant. > > > > By configuring Cassandra for security using the documentation here - > > http://www.datastax.com/docs/0.8/configuration/authentication , we were > > able to apply the security constraints on the common keyspace and common > > CFs. However this does not prevent a tenant from retrieving data > belonging > > to another tenant. For this to happen, we would need to have separate CFs > > and/or keyspaces for each tenant. > > Looking for more information on the topic here > > > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Mult i-tenancy-and-authentication-and-authorization-td5935230.htmland > > other places, it looks like the recommendation is "not" to create > > separate CFs and KSs for every tenant as this would have impacts on > > Memtables and other memory issues. Does this recommendation still hold > > good? > > With jiras like > > https://issues.apache.org/jira/browse/CASSANDRA-2006resolved, does it > > mean we can now create multiple (but limited) CFs and KSs? > > More generally, how do we prevent a tenant from intentional/accidental > data > > manipulation of data owned by another tenant? (given that all tenants > will > > provide the right credentials) > >
