[squid-users] Performance

[Alex Rousskov]

On 01/15/2018 11:56 AM, Snyder, Brian wrote:
> I have not found an issue the hardware. 

To avoid misunderstanding, I did not imply that there are
hardware-related issues. My question was about bottlenecks (i.e.,
resources that are being overused, including hardware resources like CPU
or RAM and soft resources like the number of file descriptors or
conntrack buckets).


> Atop shows everything in normal ranges.

If all resource usage is normal when the problem is apparent, then the
source of the "over time it slows down significantly" problem most
likely lies outside of Squid. An external agent (e.g., a parent proxy,
an adaptation service, a DNS server, etc.) must be delaying or dropping
messages. You can narrow down the list of suspects by investigating
Squid-reported errors and identifying Squid transaction stage(s) that
incur delays. Squid logs various transaction response times and error
details that may help in this analysis.


HTH,

Alex.


> On Jan 11, 2018, at 2:23 PM, Alex Rousskov <rousskov at measurement-factory.com<mailto:rousskov at measurement-factory.com>> wrote:
> 
> On 01/11/2018 10:14 AM, Snyder, Brian wrote:
> 
> I apologise for asking another squid performance question,
> 
> There is nothing wrong with that! It is often very difficult to solve
> performance problems on the mailing list, but that does not imply folks
> should not ask performance questions.
> 
> 
> over time it slows down significantly.
> 
> In case nobody looks for or finds problems in your configuration: What
> is the bottleneck? CPU? RAM? Disk I/O? NIC interrupts?
> 
> A tool like atop may be able to answer that question for you, especially
> if you let it collect stats from before Squid start to the time when the
> Squid becomes very slow.
> 
> Alex.
>