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

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
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.
Received on Mon Jul 26 2010 - 20:26:13 MDT