[CentOS] CentOS 5 - problem with kernel/process: task blocked for more than 120 seconds.

On Wed, 11 Apr 2012, m.roth at 5-cent.us wrote:

> Been seeing that on 6.2, also, though I've not noticed them locking up
> (the ones that have were in a cluster, and someone could have hosed
> memory). It got less with the latest kernel, but I'm still seeing them
> occasionally.

This is most likely a problem due to data arriving too quickly for the VM 
subsystem to flush dirty pages to disk to keep up; the kernel switches to 
synchronous mode when the dirty_ratio percentage of memory pages is used. 
You might try upping your dirty_ratio, or reducing it drastically.

Steve