Fresh Fedora 11 fetches 362MB+ of updates, where's deltaRPM?

Jonathan Dieter jdieter at gmail.com
Fri Jun 12 19:20:10 UTC 2009


On Sat, 2009-06-13 at 00:26 +0530, Rahul Sundaram wrote:

> Correct but if they do mirror delta rpm's they would get higher I/O
> since clients would be fetching a series of smaller packages instead of
> bigger ones.

I don't know much about mirroring, but I wouldn't think this is a huge
problem.

> There is also some additional processing required on the
> Fedora infrastructure to generate the deltas

If the OP is still following this thread, this is the real problem at
the moment.  While applying a deltarpm is a linear operation, creating
it is somewhere closer to O(N^2).  For a large package, even if Fedora's
infrastructure has loads of RAM, it still takes a number of minutes to
create a deltarpm.  Multiply that by four architectures, two releases
(well, one at the moment) and Rawhide, and the compose times
skyrocket.  

The Fedora infrastructure team is trying to streamline the process a
bit, but the fact remains that generating deltarpms costs a lot in CPU
time and RAM usage, and the more deltarpms you generate, the more time
it takes.

> and on client side to build the full RPM package from the deltas. So
> it is a trade-off.

Jonathan
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