Re: [squid-users] Will Delayed Pools to help with squid fetching content?

On Mon, 26 Jul 2010 15:56:12 -0430, Jose Ildefonso Camargo Tolosa
<ildefonso.camargo_at_gmail.com> wrote:
> On Mon, Jul 26, 2010 at 3:41 PM, Leonardo Carneiro
> <chesterman86_at_gmail.com> wrote:
>> On Mon, Jul 26, 2010 at 4:57 PM, Jose Ildefonso Camargo Tolosa
>> <ildefonso.camargo_at_gmail.com> wrote:
>>> Hi!
>>>
>>> On Fri, Jul 23, 2010 at 8:31 PM, Amos Jeffries <squid3_at_treenet.co.nz>
>>> wrote:
>>>> Etienne Philip Pretorius wrote:
>>>>>
>>>>> Hello List,
>>>>>
>>>>> I am running Squid Cache: Version 3.1.3. and I wanted to cache
windows
>>>>> updates and applied the suggested settings from
>>>>> http://wiki.squid-cache.org/SquidFaq/WindowsUpdate but now I am
>>>>> experiencing
>>>>> another problem.
>>>>>
>>>>> It seems that while I am able to cache any partial downloaded files
>>>>> with
>>>>> squid now, I am flat-lining my break out onto the Internet. I just
>>>>> wanted to
>>>>> check here before attempting to implement delayed pools. As I see
it,
>>>>> it is
>>>>> squid fetching the file at maximum speed possible.
>>>>>
>>>>> So my question is, if I implement delayed pools for the client
>>>>> connections
>>>>> - will squid also fetch the files at those reduced rates?
>>>>
>>>> Not directly. Squid will still fetch the files it has to at full
speed.
>>>> However, indirectly the clients will be delayed in their downloads so
>>>> will
>>>> spread their followup requests out over a longer time span than
without
>>>> delays.
>>>
>>> I remember and old thread about a similar situation: it was a person
>>> who was trying to use squid for an ISP, but subscriber connections are
>>> a lot slower than ISP's connection to the Internet, and so: when a
>>> client started a download for a 600MB file, squid would fetch the
>>> whole file using a lot of bandwidth, and the client would not even be
>>> at 10% of the download, so.... if the client decided to cancel the
>>> download at say, 25%, there would be a lot of wasted bandwidth.
>>>
>>> Can that situation be corrected with delay pools? or, what do you need
>>> to correct that? The desired behavior is that squid actually follows
>>> the download at the speed of the fastest client!, instead of its
>>> connection to the Internet.
>>>
>>> What do you think?
>>>
>>> Sincerely,
>>>
>>> Ildefonso Camargo
>>>
>>
>> I think this kind of bandwidth limitation you're aiming shoud be done
>> with layer 3 and 4 tools, like queues etc. Otherwise, there will be
>> wasted bandwidth, like you said.
>
> The problem is: how do you know, from the point of view of the queue
> (say, tc with htb), that a certain connection comming from the squid
> cache belongs to a particular client? (well, a wacky method comes to

TOS. Assigned to each request on the same identical criteria as delay
pools is assigned.

> my mind: use one proxy IP per client IP, but that would be an admin
> nightmare).... but, the thing is: I don't see what is the advantage of
> the proxy fetching all the file at max speed, maybe, fetching up to 1
> or 2 MB ahead of the client (maybe and amount that makes sense
> according to client's speed) could be useful, but "leaving the client
> behind", I find it a little pointless.
>
>>
>> But i also have a doubt. Will the delay pools be applied when the
>> request is a cache or mem hit or only when the request is a miss?
>>
>
> Now... that's a good question.

Yes. Delay pools is on bytes written out to the client. Regardless of
source.

Amos
Received on Tue Jul 27 2010 - 05:23:03 MDT