I guess I’ve been using Gentoo now for just a little over a year. It’s quite nice in my opinion, and have multiple servers running it. I’ve not really had any issues with it until recently.
Gentoo uses a packaging system called Portage, it’s basically a bundle of files with details for the emerge programs to use for installing packages. Recently it’s become incredibly slow when updating the package listing. I generally ignored it, as I usually kick it off inside a screen session, and logoff.
Today I decided to quit ignoring it, and start investigating. I started with the Gentoo forums, and really didn’t have to go too far. It appears I’m not the only person having this issue. I stumbled across this thread which goes over various different possibilities in the delays, but they all seemed to agree that the cause was in the updating of the portage cache. After reading a few pages, I found this page which has an interesting suggestion on the second posting. The instructions basically go into telling rsync to ignore the KDE ebuild files. I tried, and sure enough, emerge --sync now takes a lot less time, and no longer hangs for me.