Hello,
let me introduce myself, I am system admin for about 160-180 people with three squids (including 2x ipfire) in my network and many more squids in motherconcern's connected intranet. We have three connections to the internet, two separate lines (each one is secured by ipfire) and another way to internet over intranet. 1x ADSL 2MBit 1x ADSL 16/1MBit 1x intranet internet 8/8 (but shared with business critical services)
So as you might expect, there is a hard way of deciding which request goes where and where should what content be cached. I agree to Fajar's intention! We need a way more dynamic content caching capability.
Please check this: http://wiki.squid-cache.org/ConfigExamples/DynamicContent/Coordinator
here you can read about Store_Url_Rewrite
<Quote> *Pros:*
**
- *simple to implement.*
*Cons:*
- *works only with squid2 tree* - *The check is done based only on requested URL. in a case of 300 status code response the URL will be cached and can cause endless loop.* -
*There is no way to interact with the cached key in any of squid cache interfaces such as ICP\HTCP\Cache Managerhttp://wiki.squid-cache.org/Features/CacheManager, the resource is a GHOST.*
*(I wrote an ICP client and was working on a HTCP Switch\Hub to monitor and control live cache objects)*
- *To solve the 300 status code problem a specific patch was proposed but wasn't integrated into squid.* - *The 300 status code problem can be solved by ICAP RESPMOD rewriting.*
</Quote>
It is like deprecated and mentioned as "Old methods".
I think the way to go is an written Addon for squid which does the needed work. Here is a point to start reading about: http://wiki.squid-cache.org/Features/AddonHelpers#HTTP_Redirection http://www.squid-cache.org/Doc/config/url_rewrite_program/
Okay that was a lot of text without providing any helpful work, but squid is not easy and should be wisely planned. As you have to care for a lot of things like privacy, bandwidth, filesystem, cache-methods and of course you need to care about "how" your users use the web before you can optimize it.
In the company I work in, it is as follows: The most traffic is secured (HTTPS). Just think about the hosting providers like Dropbox, Google-Drive, and so on. There probably are files which are needed by many people and then downloaded by them, and you can't legally cache them. That's a shame.
My top one place of traffic per week is dropbox, but can't cache anything at the moment... A way of caching is needed which *breaks! *the privacy issue for big files only(maybe >200KB), then stores it *once* and delivers per request, no matter of the URL.
Well, just wanted to say we need to improve the caching itself and hopefully I can be of any help for this.
Best Regards Jan
2013/3/6 Michael Tremer michael.tremer@ipfire.org
Hello,
On Wed, 2013-03-06 at 16:57 +0800, Fajar Ramadhan wrote:
Hello there, replying inline
Any other ideas?
Hyper Cache
That's a possibility. I didn't know that anyone is still using the word hyper :D
Michael from IPFire.org told me that you may have some
requirements or
ideas for an improved update accelerator
Firstly, this idea is not part of update accelerator thingie.
Well, we are thinking about a rewrite, so every idea is welcome. Nobody promises that it will be implemented, but in the process of searching for the real purpose of the update accelerator, feel free to write anything on your mind if you think it is worth considering.
cause we plan to extend the current version (at this point it look like a complete rewrite
o_O)
complete rewrite, maybe :)
?
My idea is basically out from squid 2.7 abilities to cache dynamic contents using built-in storeurl feature. http://www.squid-cache.org/Doc/config/storeurl_rewrite_program/
As we are looking into the (far) future, we cannot possibly stick to an old version of squid. Even the currently in IPFire 2 running version 3.1 is "old" right now.
Maybe it is also a good idea to design this without considering squid as the default thing to work with it. It should be possible to drop squid and use an other proxy server - although I really don't have plans for that right now, because squid is the best proxy server one can have.
Wiki for example how to use storeurl http://wiki.squid-cache.org/Features/StoreUrlRewrite
We already know that squid 2.7 is already obsolete - but this feature was extremely useful for slow internet users (just like me in Indonesia, where bandwidth is expensive). Built-in storeurl feature inside squid 2.7 has ability to cache or manipulating caching for dynamically hosted contents (dynamic contents). Example for Facebook's CDN :
It is interesting that this has not been ported to squid 3.x. Apparently, the reason is that this the implementation was poorly written and so people thought about replacing it entirely. It also looks like there are not many users of this feature.
If squid already cache one of this picture then all same pictures from hprofile-ak-prn1, hprofile-ak-prn2, hprofile-ak-prn3 ..... hprofile-ak-prnX will result cache hit - squid not necessary to fetch same content from different cdn urls, since its already in cache and request got rewritten by storeurl. All contents from Facebook such as javascript, css, image, even sound and videos will have very high chance to get hits from squid.
Looking at your user data your provided further below, the important stuff to cache is big files. That's not only video and all sorts of downloads. Nowadays javascript code of sites like Facebook is of the size of one or two megabytes*.
- Didn't check. Read this somewhere, some time ago.
What I get from this is that we should design the rewrite to literally cache anything.
A technical question from me: Why cannot we use the internal cache of squid to do so, but code our own caching proxy that is actually queried by the real caching proxy? I think even with a very fast implementation, squid will always be much faster.
This method works on almost all web that serving dynamic contents for its visitors : Youtube videos (all resolutions) , blogger.com contents, online games patch files, google maps, ads, imeem, etc. This is something that you cannot done with squid 3.x.
This cannot be done with squid 3 AT THE MOMENT.
Another approach to make it work on squid 3 is using ICAP - I'm not familiar with this one since I never used it. You can see some reference about ICAP to cache dynamic contents here (for me it seems difficult to do it) : http://www.squid-cache.org/mail-archive/squid-users/201206/0074.html
As pointed out earlier, I like ICAP. The protocol has a lot of advantages and makes us independent from squid (not to replace it, but being not dependent on a certain version - they all talk ICAP).
Can someone find out if somebody already implemented this kind of thing?
Terima kasih, -Michael
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