As stated some time ago, I had the problem that users vanished after some time.
As I get a lot of e-mails regarding this problem, I therefore documentate here the details I've found out so far:
Ncsd works unreliable
Yes, indeed, switching off nscd removes the problem.
But there are more problems I experienced with nscd:
- Sometimes it consumes 100% cpu (and does not stop that until being killed)
- Sometimes it just crashes.
- Sometimes it causes users to "vanish" (the original problem)
- Sometimes it hangs and thus slows down the whole system
The alternatives
In D-INFK department in the ETH we're heavily dependent on the LDAP database, as most services are using it as its primary database. To overcome the problem, there are several solutions:
- Dump the ldap database into standard /etc/passwd and /etc/shadow
- Shutdown nscd and let the LDAP-Server handle the load
- Install unscd
I'm going for the last one now.