Re: [gentoo-dev] Proposal for an alternative portage tree sync method

[Karl Trygve Kalleberg]

Ricardo Correia wrote:
> Hi,
> Please read the following proposal, I think you'll be interested:
>
> http://forums.gentoo.org/viewtopic-p-2218914.html

I find this to be a very intriguing idea for several reasons:

1) If you're behind a restrictive firewall, you're a lot better off
    with zsync than webrsync.

2) Presumably, the CPU load on the server will be a lot better for
    zsync scheme than for rsync: the client does _all_ the computation,
    server only pushes files. I suspect this will make the rsync servers
    bandwidth bound rather than CPU bound, but more testing is required
    before we have hard numbers on this.

3) You'll download only one file (an .ISO) and you can actually just
    mount this on /usr/portage (or wherever you want your PORTDIR).
    If you have (g)cloop installed, it may even be mounted over a
    compressed loopback. A full ISO of the porttree is ~300MB,
    compressed it's ~29MB.

4) It's easy to add more image formats to the server. If you compress
    the porttree snapshot into squashfs, the resulting image is
    ~22MB, and this may be mounted directly, as recent gentoo-dev-sources
    has squashfs support built-in.

5) The zsync program itself only relies on glibc, though it does not
    support https, socks and other fancy stuff.


On the downside, as Portage does not have pluggable rsync (at least not 
without further patching), you won't be able to do FEATURES="zsync" 
emerge sync.


For interested parties: I am field-testing this on 
gentooexperimental.org. Plain ISOs work now,  as do squashfs images. 
Compressed isos are still untested, as I don't have the cloop kernel 
module installed.

I'll get back with more details in a bit when we're ready for more 
widespread testing.


> If you could reply in the forum, it would be great :)

I don't believe in forums;)

-- Karl T

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