[Server-devel] ToDO: Write up Proxy Strategy

Adrian Chadd adrian at squid-cache.org
Sun Jan 18 08:56:17 EST 2009


As I've said before, if someone would like work with the Squid
project, or my Squid-2 fork (cacheboy), I'm happy to work with them to
improve the proxy situation for the OLPC infrastructure.

Someone has to work with me though. :) I'm busy as it is trying to
rewrite code in general.

Implementing rproxy for cache peering as a transfer-encoding would be neat. ;)



Adrian

2009/1/13 Martin Langhoff <martin.langhoff at gmail.com>:
> On Tue, Jan 13, 2009 at 11:42 AM, Caroline Meeks
> <caroline at solutiongrove.com> wrote:
>> rproxy - write down what needs to be done and how much.
>
> Caroline and others pointed out today at xocamp that the rproxy notes
> were never fully documented. There are some emails on this list about
> it - but nothing complete. I've now put it in the wiki
> http://wiki.laptop.org/go/XS_Blueprints:rproxy - here's the initial
> version for discussion...
>
> Notes on an rproxy implenentation for the XS.
>
> We want to have an optional, easy to switch on rproxy setup on the XS.
> rproxy can replace or complement the main XS http proxy - if we have a
> stable, efficient, high quality http proxy on the XS, pairing it with
> rproxy would be a good idea.
>
> As long as we are using Squid, it's not such a good idea :-(
>
> =Rationale=
>
> rproxy is a proxy that expends HTTP 1.1 proxying and provides much
> better performance over very bandwidth constrained linkes. It requires
> an "upstream" rproxy to match the downstream rproxy. For deployments
> where the schools are connected to the internet with very limited
> uplinks, rproxy can be a huge win.
>
> Modern internet is made of moderately dynamic content --- the content
> is mostly static but un-cacheable due to rotating banners or "latest
> news" boxes on the side. Even when content changes, the template for
> the content is often 80% of the HTML downloaded. rproxy provides huge
> gains with such content.
>
> More about what rproxy is
> * http://rproxy.samba.org/
> * http://ozlabs.org/~rusty/rproxy.html
>
> =How it would work=
>
> For a deployment with limited connectivity into the schools
>
>  - setup a co-located rproxy server at the ISP
>  - enable rproxy on the XSs deployed, pointing to the ISP
>
> Note: the rproxy server at the ISP must only accept requests from
> valid clients - either from a defined netblock or whitelisted IP
> addresses. An open rproxy is an open proxy!
>
> =Issues with rproxy=
>
> * The working version uses an old version of librsync - which may have
> odd bugs and is generally unsupported, untouched, unknown
> * There's a half-finished port to the new librsync. Martin Poole
> started it a while ago, and abandoned it.
> * Does not stream the content through - blocks until the content is
> fully fetched before delivery to requester.
> * Unknown performance and memory footprint when hit by many users concurrently
> * Needs packaging, init scripts, etc...
> * Unclear if it behaves reasonably well with ajax "streamed" requests
> - it may break or add problematic latencies, etc
>
> =TO DO=
>
> * Test and ensure it works with modern internet usage patterns. Gmail,
> youtube, etc...
> * package, configuration, init scripts...
> * Test under load, paired with a conventional http proxy - may need
> performance / memory trimming
> * Port to modern librsync
> * Make it work with streamed content (possibly the hardest task!)
>
>
> ..
>
> cheers,
>
>
>
> martin
> --
>  martin.langhoff at gmail.com
>  martin at laptop.org -- School Server Architect
>  - ask interesting questions
>  - don't get distracted with shiny stuff  - working code first
>  - http://wiki.laptop.org/go/User:Martinlanghoff
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>
>


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