Here's a list of commands that you should execute and then share the output to someone who can help you figure out what resource is the bottleneck in your system. Note, it requires the sysstat and procps packages (ubuntu and RHEL and its derivatives): uptime vmstat 1 10 iostat -xN 2 10 mpstat -P ALL 3 10 pidstat 1 10 free -mw (or free -m, if your OS doesn't support -w) uptime is to see the load averages on the system. vmstat is mostly used to tell if the system is swapping or not. If you see significant numbers in the 'si' and 'so' columns, your system is most likely swapping (using the hard drive as RAM), which usually slows performance a lot. iostat is mostly used to determine if your disk subsystem is not able to cope with the load. If you see one or more lines that shows 100 or close almost constantly, it is probably the case. If it is your swap volume, you probably saw numbers in the 'si' and 'so' columns in the vmsta
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I recommend always to create an rpm. For example here: http://centos4.centos.ec/i386/repodata/repoview/milter-greylist-0-3.0-5.html you will find milter-greylist packaged. Therefore upgrading it, or deleteing, even the install process will be easier.