replication

When using mongodb in a replica set configuration (1 arbiter, 1 primary, 2 slaves); how do I set a preference that read be performed against the secondaries and leave the primary only for writes? I'm using MongoDb 2.0.4 with Morphia. I see that there is a slaveOk() method, but I'm not sure how that works. Morphia http://code.google.com/p/morphia/ Details My Mongo is set with the following options: mongo.slaveOk(); mongo.setWriteConcern(WriteConcern.SAFE); I am attempting to use the following (this may be answer -btw): Datastore ds = getDatastore(); Query<MyEntity> query = ds.find(MyEntity

We have a geo-replicated database in SQL Azure (Premium) and are wondering if we are pointing to the South Central US database that is the master, if that goes down do we have to manually change our connection strings in our code (C# .Net / Entity Framework 6) to point to the new database in say North US? We are looking for a way to have a single connection string and then Azure do the under the covers to now point to the new database if the master ever goes down. Is that possible? Update on method followed: so I read this that we have to manually go into a web.config file on a production

I'm currently investigating how to use the RMI distribution option in ehcache. I've configured properly ehcache.xml and replication seems to work fine. However I've 2 questions: -> It seems ehcache/ hibernate creates 1 cache per Entity. This is fine, however when replication is in place it create 1 thread / cache to replicate. Is this the intended behavious ? As our domain is big, it creates about 300 threads, which seems to me really big -> Another nasty consequence is that the heartbeat messagre seems to aggregate all of those cache names. From what I saw the message should fit in 1500 bytes

Does Cassandra replicate only on write procedure (with chosen consistency level)? Is there any auto-replicate option for absent nodes, if I want symmetric data in every node? If I plug in a new node to the cluster, there is no auto replication. How can I sync data from other nodes with the new one? If I want replication like multimaster (2 nodes) with slave backup (1 node) known from MySQL, what is the proper way to set up and manage that on Cassandra (3 nodes)? How about two nodes? Cassandra replicates on writes, yes, but it also uses Hinted Handoff , Read Repair and Anti Entropy to to reduce

We started some overseas merge replication 1 year ago and everything is going fine till now. My problem is that we have now so much data in our system that any crash on one of the subscriber's servers will be a disaster: reinitialising a subscription the standard way will take days (our connexions are definitely slow, but already very very expensive)! Among the ideas I have been following up are the following: make a copy of the original database, freeze it, send the files by plane to the subscriber, and initiate replication without snapshot: this is something that was done traditionnaly with