On Wed, Oct 21, 2009 at 4:01 PM, Greg Smith <gsmith@gregsmith.com> wrote:
> On Wed, 21 Oct 2009, Waldomiro wrote:
>
>> top - 16:16:30 up 42 days, 13:23, 4 users, load average: 3.13, 3.52,
>> 3.36
>> Cpu(s): 1.4%us, 1.1%sy, 0.0%ni, 84.4%id, 12.9%wa, 0.0%hi, 0.2%si,
>> 0.0%st
>> Mem: 16432240k total, 16344596k used, 87644k free, 27548k buffers
>> Swap: 10241428k total, 3680860k used, 6560568k free, 6230376k cached
>>
>> I'm afraid of two things, one is the "load average", I think 3 is too much
>
> You're at 12.9% waiting for I/O and 84.4% idle. That means your average
> load consists of three processes who are stuck waiting for I/O at any given
> time. The I/O is what you should be worried about, not the load average.
>
>> another is the "swap", almost 4GB of swap, I think that is too much swap.
>
> It does look like your server is using much more RAM than it actually has,
> which is the likely reason for all the disk I/O. If you sort the top output
> by memory, you might see why that is.
This is a common misunderstanding.
In this:
Mem: 16432240k total, 16344596k used, 87644k free, 27548k buffers
Swap: 10241428k total, 3680860k used, 6560568k free, 6230376k cached
The 6.2G cached is considered part of the 16G used
So it's not using more memory than it has. It's just the accounting
is inobvious.