Downloads with delta RPMs in Fedora-11

Yesterday while doing some goggling I come across through “Delta RPM Packages” in Fedora 11, which is a great new feature: delta RPM updates. This feature creates delta RPM packages (.drpm) that are binary “patches” to the existing RPM packages. What this package does is that it downloads only the changes of the RPM as compare to the existing RPM instead of downloading the full RPM package.

Once the delta RPM is downloaded by the Presto plugin for yum, it will try to reconstruct a full RPM based on the contents of the previous RPM, plus the newly changed files from the delta RPM. Yum will then install the newly-created RPM.
Using Presto has its benefits and drawbacks. If we have a fast Internet connection or are using a local mirror, using Presto doesn’t make sense. It would be faster to download the full RPM package instead of downloading the changed parts and consuming CPU time to reconstruct the RPM to install. You can get detail information about Presto from Fedora Project, Click Here

If, however, we have a slow Internet connection using Presto makes sense: it will download smaller files which will save time, money and resources.
Presto will depends mostly on the update. If it is an update that introduce a single patch that affects only one or two files among multi-megabyte package then using Presto will make the download really fast, if it’s an upgraded version being provided and most files would likely change meaning that many files have changed and been downloaded.

To use Presto, All we need to do is install the yum-presto package, which contains the plugin for Presto:

# yum install yum-presto

Once this is done, we can call to yum using Presto with no further configuration on our part. If you don’t want to use it any more just we have to simply remove the yum-presto-package.

# rpm -e yum-presto

After this in next using yum will act as normal, NOTE: Presto is not the default in Fedora-11 but what look from the application is that it will be the default in Fedora-12.

I Hope this will be informative for you :)