rm -rf /var/db/repos/gentoo
cp /usr/share/portage/config/repos.conf /etc/portage/repos.conf
sed -i "/sync-uri = rsync:\/\/rsync.gentoo.org\/gentoo-portage/async-uri = https://anongit.gentoo.org/git/repo/sync/gentoo.git" /etc/portage/repos.conf
sed -i "/sync-uri = rsync:\/\/rsync.gentoo.org\/gentoo-portage/async-type = git" /etc/portage/repos.conf
sed -i "s/sync-type = rsync/# sync-type = rsync/" /etc/portage/repos.conf
sed -i "s/sync-uri = rsync:\/\/rsync.gentoo.org\/gentoo-portage/# sync-uri = rsync:\/\/rsync.gentoo.org\/gentoo-portage/" /etc/portage/repos.conf
emerge --sync

当然也可以手动更改
sync-type = rsync -> sync-type = git
sync-uri = rsync://rsync.gentoo.org/gentoo-portage -> sync-uri = https://anongit.gentoo.org/git/repo/sync/gentoo.git

改了之后 emerge-webrsync 就不能使用了