Quality of Service(QOS)specification Qos can be specified on )A Destination Maximum QOS can be defined on a Destination(e. g. this Destination can only accept non-persistent messages A message By individual Producers, typically under application control via a combination of API calls( e.g. JMS Persistent or Non-persistent) and the Connection Factory used (which defines the Persistent/NonPersistent IBM Software Group I Web Sphere software Destination Quality of Service for Reliability BEST EFFORT NONPERSISTENT b Messages are never written to disk b throw away messages if memory cache over-runs EXPRESS NONPERSISTENT cache overruns, but are not kept over server restarts b No acknowledgement that the ME has received the message RELIABLE NONPERSISTENT sage that the client raits for. before turning to the application with an OK RELIABLE PERSISTENT rmal processing, and stay persisted over server restarts. aung b If the server fails, messages are lost if they are held in the cache at the ASSURED PERSISTENT b Highest degree of reliability where assured delivery is supported8 IBM Software Group | WebSphere software WebSphere Application Server v6 15 Quality of Service (QOS) specification ƒ QOS can be specified on A Destination ƒ Maximum QOS can be defined on a Destination (e.g. this Destination can only accept non-persistent messages) A message ƒ By individual Producers, typically under application control via a combination of API calls (e.g. JMS Persistent or Non-persistent) and the Connection Factory used (which defines the Persistent/NonPersistent Mapping) IBM Software Group | WebSphere software WebSphere Application Server v6 16 Destination Quality of Service for Reliability ƒ BEST_EFFORT_NONPERSISTENT Messages are never written to disk throw away messages if memory cache over-runs ƒ EXPRESS_NONPERSISTENT Messages are written asynchronously to persistent storage if memory cache overruns, but are not kept over server restarts No acknowledgement that the ME has received the message ƒ RELIABLE_NONPERSISTENT Same as Express_Nonpersistent, except, we have a low level acknowledgement message that the client code waits for, before returning to the application with an OK or not OK response ƒ RELIABLE_PERSISTENT Messages are written asynchronously to persistent storage during normal processing, and stay persisted over server restarts. If the server fails, messages are lost if they are held in the cache at the time of failure. ƒ ASSURED_PERSISTENT Highest degree of reliability where assured delivery is supported High Low Performance Low High Reliability