Re: Occasional giant spikes in CPU load

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On Wed, Apr 7, 2010 at 3:57 PM, Craig James <craig_james@xxxxxxxxxxxxxx> wrote:
> On 4/7/10 3:36 PM, Joshua D. Drake wrote:
>> My guess is that it is not CPU, it is IO and your CPU usage is all WAIT
>> on IO.
>>
>> To have your CPUs so flooded that they are the cause of an inability to
>> log in is pretty suspect.
>
> I thought so too, except that I can't login during the flood.  If the CPUs
> were all doing iowaits, logging in should be easy.

No - logging in with high iowait is very harder to do than high CPU
time because of latency of disk access.

> Greg's suggestion that shared_buffers and work_mem are too big for an 8 GB
> system fits these symptoms -- if it's having a swap storm, login is
> effectively impossible.

A swap storm effectively puts the machine into very high iowait time.

-Dave

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