I work on a web application that uses custom in-house key-value store. This web application also has custom in-house replication support which unfortunately has a lot of room for improvement and does not meet reliability requirements, so I want to rewrite this, if possible.
I’m looking for a java library that would allow me to build replication support on top of that custom persistence layer. It does not look super hard to write, given my requirements but definitely I’d rather reuse a good library than build my own (which is at least several dev/months of work).
In particular, I’d like to see things like:
- ability to delegate conflicts resolution to the application,
- ability to delegate data persistence concerns to the application (so I can use my own data store),
- socket pools and abstraction on top of data interchange between hosts in the replication hosts group,
- replication logs (support of basic recovery from temporary outage),
- ability to configure participants,
- ability to add/remove host to the replicated group,
- ability to apply replicated modifications in order of occurrence (so it also needs something like distributed counter),
- also (nice to have) ability to configure consistency levels, or at least choose between eventually consistent updates and strongly consistent updates for certain types of modification. I’m not looking for comprehensive solution (like Cassandra) but I’m looking for a library that doesn’t enforce underlying persistence layer (so I can choose how I store the data locally).
I’d appreciate any hints or any examples of such functionality in java.