System update spec proposal

[Ivan Krstić]

On Jun 26, 2007, at 10:19 PM, tridge at samba.org wrote:
> Internally rsync is a pretty delicate piece of code (sorry about
> that), and it would be easy to introduce a subtle bug that corrupted
> files. The basic idea of mmap hack is certainly good, I am just wary
> of trying to say how long it would take to get right.

This is a very useful data point because it means that rsync might --  
with some careful work, but not too much of it -- become a long-term  
solution for our use case in addition to being a very appealing short- 
term one. It's still my *strong* hunch that we are not going to run  
into any issues whatsoever given our update sizes and the fact that  
we're serving them from reasonably beefy school server machines, so  
adding this functionality to rsync would easily be a post-FRS goal.

Scott, are you willing to do a few tests and grab some real numbers,  
using previous OLPC OS images, for resource utilization on the school  
server in the face of e.g. 5, 10, 20, 50 parallel updates?

--
Ivan Krstić <krstic at solarsail.hcs.harvard.edu> | GPG: 0x147C722D