Re: [squid-users] squid accel peer load balancing weighted round robin?

Sylvain Viart wrote:
> Hi Chris,
> Chris Robertson a écrit :
>>> I've a squid Version 2.6.STABLE16
>>> with the following config accel mode design:
>>>
>>> proxy ----> php-01..php-08
>>>
>>> php are apache server no slibing proxy.
>>
>> If things haven't changed, weight only works with ICP. Basically an
>> ICP query is sent out, and the weight is added to an internal
>> calculation based on response latency (and possibly other factors) to
>> determine which affirmative responding ICP peer to request the actual
>> object from.
> Ok, that what I suppose too. weight seems to be for ICP slibing proxy.
> What I want effectively is, weighted round robin on origin server.

As far as I can tell, CARP would do that. I haven't tested it though.

>
> And it seems, that perform, round bobin as expected. But it may also
> be disturbed by some other peer in my definition. Here is the complement:
>
> I define 8 peer, for php content, and 1 for static content, as you can
> see on the max-conn peer doesn't allow the same load. I first try to
> modify the weight introducing the strange behavior I described.
> The config I show is my new test, with url_rewriter weighted round
> robin. Which seems to work as expected.

SNIP
Fair enough. Clever solution.

>> Squid 3's conf file seems to confirm this
>> (http://www.squid-cache.org/Versions/v3/3.0/cfgman/cache_peer.html):
>>
>> use 'weight=n' to affect the selection of a peer during any weighted
>> peer-selection mechanisms. The weight must be an integer; default is
>> 1, larger weights are favored more. This option does not affect
>> parent selection if a peering protocol is not in use.
> Seems also for ICP proxy, even weighted-round-robin, an squid3 option,
> seems to be related to ICP proxy.

Agreed.

SNIP

>>> All my test seem to show always very more load on the last peer in
>>> the list. That why I protect with max-conn=100.
>>
>> How are you measuring load? Round-robin is exactly what it sounds
>> like. Each request is sent to the next peer in line. Processing
>> load is not taken in to consideration.
> I measure load by looking on some MRTG like graph of all the server
> pool. And clearly it see, than the load is badly divided on each peer.
> But if it's supposed to work with slibing proxy, I can live with that
> somewhat bug. :-)

Very odd.

>> CARP is purpose build load balancing algorithm, and as far as I know,
>> it should work with originserver.
>> http://docs.huihoo.com/gnu_linux/squid/html/x2398.html
> Yep, I saw it too. Seems to be also for slibing proxy, no?

Designed for sibling proxies, yes. But it doesn't seem to require ICP,
so should work with non-ICP peers (and therefore acceleration setups).
As I stated, I haven't tested this theory.

>
> Thanks for you comment.

Sorry they weren't more helpful.

>
> Regards,
> Sylvain.

Chris
Received on Wed Oct 31 2007 - 14:45:21 MDT