I have an Apache webserver on CentOS. It is not doing anything fantastic or complicated at all but it does at intervals experience a high load (120 for 4 CPUs) for some reason. During this time I see high waits and write durations. I have narrowed this down to flushing of dirtypages to disk to make room for new data. I have tried many things and talked to the developers who are also puzzled by this. I am stumped. Details: vmware virtual guest server 4 cpus 12G RAM Apache PHP I have 40 servers in this cluster that share the same disk structure. Only the webservers are experiencing this issue. Any ideas?