> We have to mail servers running qmail + vpopmail 5.3.9
> The second server should get the vpopmail/domains dir via NFS from the
> first one. It seems that just the first 100 domains are working. All
> domans inside domains/0/ or domains/1/ are not recognized by the second
> server. I guess this has something to do with domains/.dir-control?
No, you must syncronize
From the first server to the second server (better with rsync), then execute
killall -HUP qmail-send
on the second server, to make it syncronize without restart qmail.