When I prepared a new ZLM test environment for a workshop, it took me the first 5 days to mirror down all SLES 10 and 11 patches to the local server. It was really annoying to see that the download rate was around 50 kB/s knowing that there were GBs of patches to download.
As my ZLM server connected directly to the Novell Update server, I had the idea to put a proxy in front of the ZLM server to speed that up. So I installed and configured the squid proxy on the ZLM server itself and added the proxy configuration to the mirror xml file and restarted the mirror.
Right after that the download rate increased to the limit of my internet access and was about 5 times higher then before. It took still some time to get all patches but it was even much faster then before.
So if you need to do the same and don’t want to waste any time, do the same.