[CentOS] server is extremly slugish - unable to troubleshoot..

Mon Aug 23 09:11:38 UTC 2010
Roland RoLaNd <r_o_l_a_n_d at hotmail.com>

Dear all,

I have a virtual machine with the following specs:

Core 2 DUO 3.2 GHZ
4 GB RAM
hdd: IDE 320 GB 
32 bit
OS: centos 5.2


I'm using it for local development with a number of Virtual hosts, and a big mysql database.

the prob:


At times, with no specific reason. system becomes extremly slugish.
http requests takes forever to be served.
Even ssh connections takes time to connect, and a simple command such as "clear" takes anywhere between 3 to 10 seconds to execute.

i've checked TOP, over and over again and it's always within the following:

CPU load average  is max 10 % , and at that specific time it's never above 30 %
RAM: swap is never used, there's always around 1.5 GB of free memory


so it's not a matter of CPU nor RAM.
so my next thought were that HDD is maxing out on the hosting physical server. 
i checked on the physical server, and HDD I/O is within normal range. and other VMs workign on the same physical server are running smoothly..

so what can i do more to troubleshoot? 
this is happening more than it should without any scenario in common.

any advice on how to troubleshoot would be greatly appreciated...


PS: any command that may show I/O in KB/MB on the HDD ? 

 		 	   		  
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