using nscd (ldap) makes passwd/group disappearing while installing ports

I'm using on a couple of servers the nameservice cache dameon nscd and
cache "group", "passwd" and "sudoers". Backend is LDAP, but local files
should searched first. then ldap. cache is searched the very first even
before files.

Well, I'd expect that if a group is present, like "cups" or "dhcp" and
reside in the local file (/etc/group or /etc/passwd), they are cached.

Installing net/isc-dhcp42-server fails with this error:


gmake[1]: Leaving directory
`/usr/ports/net/isc-dhcp42-server/work/dhcp-4.2.3-P2/server'
gmake[1]: Entering directory
`/usr/ports/net/isc-dhcp42-server/work/dhcp-4.2.3-P2'
gmake[1]: Nothing to be done for `all-am'.
gmake[1]: Leaving directory
`/usr/ports/net/isc-dhcp42-server/work/dhcp-4.2.3-P2'
===>  Installing for isc-dhcp42-server-4.2.3_2
===>   Generating temporary packing list
===> Creating users and/or groups.
Creating group `dhcpd' with gid `136'.
pw: group disappeared during update
*** Error code 70

Stop in /usr/ports/net/isc-dhcp42-server.
*** Error code 1

Stop in /usr/ports/net/isc-dhcp42-server.



I also have this error very often when rebuilding/updating or even
installing cups when "nscd" is enabled. A simple restart of nscd helps
in most cases, most times I need to disable "cache" tag in
/etc/nsswitch.conf, then everything runs smooth.

Well, this behaviour is since a couple of years now, occurs sporadic. I
have had in FreeBSD 7, 8, 9 and I see it in 10. What is it?

I like the cache facility, since in domains with a lot of users
searching LDAP takes some time and caching help keeping traffic and
latency short. But the namservice caching mechanism seems to be
unreliable. What is up there?