I've had problems with nscd crashing every few days on my CentOS 4 mail server for a while now. The problems started maybe around CentOS 4.2, although I don't remember for sure. My debugging efforts let me to disable nscd's persistent cache, and that seemed to work for a while, but since upgrading to CentOS 4.4, the crashes have started again.
When nscd crashes, the rest of the system becomes unreliable. Dovecot hangs when new users attempt to log in (fixed or worked around by switching Dovecot versions), and MIMEDefang (which we use for mail filtering) starts failing when it tries to process mail.
A bit more information about our configuration: We use nss_ldap and pam_ldap against a failover pair of Fedora Directory Servers. nscd is also crashing on another of our servers (a fileserver) but with less regularlity; on our other servers, it works fine, even without disabling the persistent cache.
Has anyone seen similar problems with nscd? Any tips for debugging it? I can use gdb, strace, etc. if I have to, but that can be time consuming, and it's hard to take the time to do that when people are yelling about the mail server being down. (Does CentOS provide debuginfo RPMs?)
Thanks.
Josh Kelley