Resin and HQ are Getting Along Again

HQ and Resin user’s might have noticed that somewhere around the Resin 3.0.2x release time frame HQ stopped collecting metrics from some key values that most folks found rather important. For example, per Webapp the following metrics were no longer being collected:

Request Count
Request Count per Minute
Request Read Bytes
Request Read Bytes per Minute
Request Time
Request Time per Minute
Request Write Bytes
Request Write Bytes per Minute

Well as of Resin 3.1.6 released on May 5th, these metrics are back! Thanks to the Engineering team at Caucho, turning on JMX statistics for these key metrics is as easy as adding <statistics-enable/> to either <web-app-default> or a specific <web-app> defined in resin.conf.  Restart Resin and like magic you’ll see metrics flowing again into HQ.

Add comment May 6th, 2008 Marty Messer

Hyperic Hints #2: False Alerts? Check System Time.

As you probably know, Hyperic HQ is an agent-based system management system. That means there is an HQ Server component and a separate HQ Agent component. When you have the HQ Server on one platform and the HQ Agent on a different platform, you run into an interesting trust issue.

The HQ Agent operates independent of the HQ Server, which is necessary because the network link between the two cannot be guaranteed to be up 100% of the time. Due to this, the HQ Server must trust the HQ Agent when it receives metric data from it. The HQ Agent stamps each metric with a timestamp before it is sent off to the HQ Server. When the HQ Server receives the metrics, it looks at the timestamp on the metric to determine when it was collected and inserts the metric into the appropriate “slot”.

Add comment February 28th, 2008 John Sachs

Hyperic Hint #1: Fixing Transaction ID Wraparound Failures in built-in HQDB

The built-in HQ database is PostgreSQL. Recently, users have been discovering PostgreSQL has a certain limitation: it will not execute more than 2 billion transactions between vacuums. In rare cases, an HQ built-in database can get into this state.

If this happens, the database will stop accepting connections and HQ, which needs a data store, will obviously cease to operate properly. The immediate symptom will be that users will not be able to log in to HQ and the message displayed on the screen will be The backend datasource is unavailable.

2 comments November 15th, 2007 John Sachs