Connections dropped under load

[Caunter, Stefan]

Even 200 is low if you regularly see a lot of traffic, but that initial setting would likely have dropped most connections. 

Sent from my iPhone

On 2011-01-10, at 19:00, "George Georgovassilis" <g.georgovassilis at gmail.com> wrote:

> Hello Stefan,
> 
> Thank you for the hint. Here are the values:
> 
> thread_pools = 2
> thread_pool_min = 2
> thread_pool_max = 200 (was 2 at the time of my initial tests)
> thread_pool_add_delay = 2
> 
> Regards,
> G.
> 
> On 11.01.2011 00:48, Caunter, Stefan wrote:
>> Hi George,
>> 
>> I assumed your management access is on port 6082. Adjust to your configured varnishd please.
>> 
>> Thread creation and pool size monitoring is essential to handling traffic spikes. If load test exceeded the configured available maximums varnish will drop connections, cache hit or no.
>> 
>> A thread is required to answer a network connection. You don't get something for nothing. Unless varnish has resources to get that cached object, it cannot do anything for your requesting clients, real or test.
>> 
>> Sent from my iPhone
>> 
>> On 2011-01-10, at 15:55, "George Georgovassilis"<g.georgovassilis at gmail.com>  wrote:
>> 
>>> Hello Stefan,
>>> 
>>> For every of the commands you quoted I'm getting an
>>> 
>>> connect(): Invalid argument
>>> Connection failed
>>> 
>>> 
>>> Why are threads relevant? As I wrote earlier, everything is answered from within the varnish cache - I thought the entire epolling parade was about avoiding caches.
>>> I published the threadsettings earlier in this discussion.
>>> 
>>> Regards,
>>> G.
>>> 
>>> On 10.01.2011 19:50, Caunter, Stefan wrote:
>>>> Yes, and I also don't understand why there is no discussion of threads
>>>> here. If we can see
>>>> 
>>>> varnishadm -T 6082 param.show thread_pools
>>>> varnishadm -T 6082 param.show thread_pool_min
>>>> varnishadm -T 6082 param.show thread_pool_max
>>>> varnishadm -T 6082 param.show thread_pool_add_delay
>>>> 
>>>> it would be helpful.
>>>> 
>>>> The only time I've seen varnish drop connections is when it cannot
>>>> create threads quickly enough, or has insufficient resources to do so.
>>>> 
>>>> Stefan Caunter
>>>> e: scaunter at topscms.com  ::  m: (416) 561-4871
>>>> www.thestar.com
>>>> 
>>>> 
>>>> -----Original Message-----
>>>> From: varnish-misc-bounces at varnish-cache.org
>>>> [mailto:varnish-misc-bounces at varnish-cache.org] On Behalf Of Kristian
>>>> Lyngstol
>>>> Sent: January-06-11 4:00 AM
>>>> To: George Georgovassilis
>>>> Cc: varnish-misc at varnish-cache.org
>>>> Subject: Re: Connections dropped under load
>>>> 
>>>> Hi,
>>>> 
>>>> On Wed, Jan 05, 2011 at 04:20:31PM +0100, George Georgovassilis wrote:
>>>>> I'm having trouble with dropped connections under a loadtest.
>>>> We need:
>>>> 
>>>> varnishstat -1
>>>> 
>>>> Any further discussion without varnishstat -1 output is wild guesswork
>>>> and
>>>> superstition.
>>>> 
>>>> - Kristian
>>>> 
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>>> 
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