samba - Mar 2014 - startsmbfilepwent_internal: unable to open file ... smbpasswd

I found the system log file filling up with the following messages:

Mar 18 02:04:16 seahorse smbd[8453]: [ID 702911 daemon.error]
[2014/03/18 02:04:16.796510,  0]
../source3/passdb/pdb_smbpasswd.c:258(startsmbfilepwent)

Mar 18 02:04:16 seahorse smbd[8453]: [ID 702911 daemon.error]
startsmbfilepwent_internal: unable to open file
/opt/local/samba4/private/smbpasswd. Error was: Too many open files

Mar 18 02:04:16 seahorse smbd[8453]: [ID 702911 daemon.error]
[2014/03/18 02:04:16.796641,  0]
../source3/passdb/pdb_smbpasswd.c:1301(smbpasswd_getsampwnam)

Mar 18 02:04:16 seahorse smbd[8453]: [ID 702911 daemon.error]
Unable to open passdb database.


I noticed this when the /var partition filled up. My smb.conf file has
'security = domain'
set and the account information is comming from a Windows 2000 Domain
Controller. It also had
'passdb backend = smbpasswd'
which was left over from before we started to use the Domain Controller.
A smbpasswd does exist. It was probably created by Samba 2.something.
I changed
'passdb backend = smbpasswd'
to
'passdb backend = tdbsam'
and the errors stopped. Samba then created a passdb.tdb file.

But with security = domain, why is Samba trying to access a password file
at all?

Tom Schulz
Applied Dynamics Intl.
schulz at adi.com