ah, then my mirroring is broken.
I'm using...
/usr/local/bin/lftp -c 'open ftp://mirrors.sonic.net && lcd /mnt/zbig/mirror && mirror --continue --verbose=1 -x ia64 -x s390 -x s390x -x alpha -x SRPMS centos'
(mirrors.sonic.net is relatively close to $job's main internet gateway).
ok, I deleted all the folders that were supposed to be symlinks on my mirror, and restarted the lftp job and NOW its creating symlinks.
maybe I screwed up when I rsync'd my old solaris-based mirror to my new freenas/freebsd based mirror.