This link describe ganglia / cassandra graphing. http://mysqldba.blogspot.com/2010/09/cassandra-and-ganglia.html
I ran into a problem illustrated here. http://www.flickr.com/photos/dathan/4971255111/ This screen shot shows a huge spike of transport exceptions between the hours of 12:15 - to 1:30. Why? Lets see. http://www.flickr.com/photos/dathan/4971869002/ This link shows that the pending reads jump because the message deserialization pool (mutex) blocks or maybe its viceversa. But Why? Lets see. This link shows that wait_io on the box sky rocketed. http://www.flickr.com/photos/dathan/4971290101/ but why? Could it be because http://www.flickr.com/photos/dathan/4971869054/ This graph shows a massive amount of data growth for this server, then it reduces but why? How can I tune it so that a growth of data doesn't explode like this? Some background information: These servers are DELL 2950 dual quad core boxes with 48GB of Ram on a RAID-10 EXT3 FS backed by 8 disks on a PERC-6 Controller with BBC. Each server rougly recieves 300-400 requests per second fronted by a F5 Loadbalancer (soon to be HA-Proxy) on least connections, doing a client stat check to verify the server is up from a client point of view. There is only one simple key space. A Super Column is defined but not used and uses a RandomPartitioner with NO RowCaching and mmap enabled.
