Jigdo - A Professional Letter to Mike McGrath

[Mike McGrath]

Jonathan Steffan wrote:
> The amount of storage and bandwidth able to be saved can be illustrated
> by a simple comparison between the efficiency of chopping up a 3.4GB
> iso9660 file system arbitrarily (by a static chunk size) and the same
> file system based on contents (file by file.) For a BitTorrent,
> Fedora's current choice for sharing Spins, the hosted data is only
> valid for a given chunk on a single ISO. This data's footprint (equal
> to the combined chunk sizes of the entire torrent) can be used for
> nothing but this Spin. To be able to host 5 Spins composed from similar
> trees via BitTorrent, we now have a footprint of 17GB, not to mention
> "seeders" have to run BitTorrent software to be able to contribute to
> the swarm. Alternatively, Jigdo can be used to reduce the footprint of
> these 5 Spins to about 4GB. The amount of additional data needing to be
> hosted for each Spin, in addition to what data is already pushed to the
> mirrors, is about 150MB per ISO with anaconda and about 200KB for ISOs
> without the installer bits. To help illustrate the efficiency of using
> Jigdo vs BitTorrent, the footprint for 250 Spins is 850GB for
> BitTorrent and about 40GB for Jigdo. Additionally, a reduction in
> overhead can be achieved by removing the need for the BitTorrent
> tracker and all related network traffic without requiring any
> additional work on the part of mirror administrators.
>   

This paragraph shows the savings we would make on the jigdo server.  How 
much would our storage needs increase by needing to keep all RPM's 
around on the mirrors?

    -Mike