[Nix-dev] Proposal for hydra with librsync

[Jeff Johnson]

On May 10, 2010, at 6:32 PM, Lluís Batlle i Rossell wrote:
> 
> I think that such a system, additionally to the rest of the nix system, would
> look astonishing compared to what other distros have.
> 

(aside)
Distributing with rsync is hardly state of the art, /nix/store _IS_
state of the art. I wouldn't bother with rsync "astonishment".

librsync is a zombie project. which is a shame, Martin Pool is a
really smart guy, just that the rsync protocol is patent encumbered
many years now.

There's zsync which _IS_ active, and also has the benefit of
burning client, not server, CPU cycles. But I haven't looked
carefully at zsync for several years.

Note that MacPorts uses rsync heavily for distributing/updating
entire distro build tree's used by port(1). You likely can steal most everything
straight from MacPorts.

Hint: make sure that you use gzip --rsyncable everywhere possible.
AFAIK neither XZ nor BZIP2 have --rsyncable sufficiently for rsync
transport to be a "win" (the transport will just degrade to plain
copy).

For extra credit: Figger how to remove rsync's innate bias
on file paths so that Nix instances could be rsync'd directly.
Now _THAT_ would be spiffy and "astonishing".

> Any volunteer to start with a hack to test this? Maybe this idea will look nice
> even for Delft people to implement it. At least I sent this letter before I
> forget.
> 

Hehe, I'd volunteer, but I assure you that I'm the last person in
the world you want being a sysadmin. ;-)

73 de Jeff