You could be seeing GC pauses. Did you increase the heap size you gave Cassandra, when you increased your VM size?
On Tue, Jun 29, 2010 at 11:57 AM, Oren Benjamin <o...@clearspring.com> wrote: > Hi all - first timer here. > > I'm experimenting with Cassandra on Rackspace Cloud. Started with 4GB nodes > and saw read latency spikes while streaming was taking place, so I increased > to 8GB to see if limited memory was the issue. Now I'm seeing very strange > behavior during any period that writes are taking place. The entire (6 node) > cluster seems to pause for periods of as much as 5-8 sec. By that I mean all > the stats (cpu, disk, network IO monitored via dstat) drop to zero or near > zero on all nodes simultaneously. Does anyone have experience with Cassandra > on Rackspace or any idea what's going on here? > > The pauses are short enough that it's difficult to introspect the application > and determine what it's doing during the pause, but long enough to cause > unacceptable latency for any service built on top of it. > > Any ideas or debugging methods would be greatly appreciated, > > -- Oren -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com
