[CentOS-mirror] Proposel - jigdo for iso Images

Thu Oct 29 19:57:21 UTC 2009
David Richardson <david.richardson at utah.edu>

On Thu, 29 Oct 2009, Uwe Kiewel wrote:

> what do you think about using jigdo for distributing iso Images?
> http://en.wikipedia.org/wiki/Jigdo
> http://atterer.net/jigdo/
> advantages:
> 	- save space at mirror because data are now redandant (as rpm's 		  and
> "inside" the iso images
> 	- the webserver does handle small files more efficient than big
> 	  files
> 	- can save bandwith if a download of an iso image aborts and
> 	  have to be restarted
> disadvantage:
> 	- maybe more requests, for downloading all rpm's to build the  			  iso
> at client site

It'll take just as much time and bandwidth for Jigdo to download the 
individual pieces as it would to just download the ISO. Modern web clients 
support resuming an aborted download, so the savings there wouldn't be 
that much (and is shrinking as clients get smarter).

It doesn't save server load: finding-opening-closing a file is not free. 
It may not hurt my load much, but it certainly will not help it at all.

It doesn't make the user's life easier: too many people won't (or worse, 
can't) install something to get the ISO. Who want to install yet another 
specialty downloader?

We'd have a lot of people unhappy if we made Jigdo mandatory. I won't 
support that idea. And if Jigdo isn't mandatory, it won't save any disk 

If someone wants to maintain the Jigdo templates and evangelise using it, 
fine, but it looks to me like a lot of effort for not much return.

If we're looking to reduce disk space used on the mirrors, dropping the CD 
images (in favor of DVDs) would be a better plan. (If you're disk-space 
constrained, you can already loop-back mount the DVD image to get the 
expanded tree.)


David Richardson <david.richardson at utah.edu>
"There are two kinds of statistics:
the kind you look up and the kind you make up."
-- Archie Goodwin, Death of a Doxy