[katello 2.3] Sync of any kind of yum repo waits a long time on Actions::Pulp::Repository::Sync


i've just set up an instance of katello 2.3. I'm now synchronizing some
repositories from the internet. In particular, the repos are puppet
packages, katello-agent packages and RHEL 6 RPMs from cdn.

I'm experiencing performance issues on the Actions::Pulp::Repository::Sync
step of the process. For example, i have started some minutes ago the sync
of RHEL 6 RPMs. 12 packages have been downloaded.

This is the Execution time informations from dynflow console:

Started at: 2015-09-08 14:12:22 UTC
Ended at: 2015-09-08 14:25:08 UTC
Real time: 765.19s
Execution time (excluding suspended state): 9.44s

The first time i did this synchronization required a so long time that the
task has been forcefully stopped after 6 days running (and obviously
finished without success).

Started at: 2015-08-26 14:40:45 UTC
Ended at: 2015-09-02 13:37:36 UTC
Real time: 601011.51s
Execution time (excluding suspended state): 277.54s

I'd like to know if this is a common issue and i only need to wait, or is a
performance issue that i have to fix in some way.

I'm running katello/foreman on a VM with 2 vCPU (Intel® Xeon® CPU
E5-2670 v3 @ 2.30GHz) and 8 GB of ram.

Thank you,