Requests suddenly slow / fine after restart

[Bjoern Metzdorf]

Poul-Henning Kamp wrote:
> In message <480875C6.60503 at turtle-entertainment.de>, Bjoern Metzdorf writes:
> 
>> Recently we had some problems with slow requests. Some static graphic 
>> files suddenly took several seconds to load instead of the usual 
>> milliseconds. After a restart of varnish everything was fine again and 
>> the very same graphic was fast again.
> 
> You want to use some tool to graph your system activity so that you can
> see what system resource is causing your grief.
> 
> Most likely it is disk-I/O, but without data it is impossible to be
> sure of that.
> 
> A lot of varnish people seem be partial to the "Munin" tool for this.
> 

We are graphing cache hits and client requests with cacti and have the 
machines in ganglia as well. I will have a look at the graphs the next 
time this happens.

Regards,
Bjoern