14.2. The Benefits of Using Hot Rod over Memcached

The memcached protocol causes the server endpoint to use the memcached text wire protocol. The memcached wire protocol has the benefit of being commonly used, and is available for almost any platform. All of JBoss Data Grid's functions, including clustering, state sharing for scalability, and high availability, are available when using memcached.

However the memcached protocol lacks dynamicity, resulting in the need to manually update the list of server nodes on your clients in the event one of the nodes in a cluster fails. Also, memcached clients are not aware of the location of the data in the cluster. This means that they will request data from a non-owner node, incurring the penalty of an additional request from that node to the actual owner, before being able to return the data to the client. This is where the Hot Rod protocol is able to provide greater performance than memcached.

JBoss Data Grid's Hot Rod protocol is a binary wire protocol that offers all the capabilities of memcached, while also providing better scaling, durability, and elasticity.

The Hot Rod protocol does not need the hostnames and ports of each node in the remote cache, whereas memcached requires these parameters to be specified. Hot Rod clients automatically detect changes in the topology of clustered Hot Rod servers; when new nodes join or leave the cluster, clients update their Hot Rod server topology view. Consequently, Hot Rod provides ease of configuration and maintenance, with the advantage of dynamic load balancing and failover.

Additionally, the Hot Rod wire protocol uses smart routing when connecting to a distributed cache. This involves sharing a consistent hash algorithm between the server nodes and clients, resulting in faster read and writing capabilities than memcached.