Samba-3 provides for complete backward compatibility with Samba-2.2.x functionality as follows :
10.1.1 Backward Compatibility Backends
Plain Text ” This option uses nothing but the UNIX/Linux /etc/passwd style backend. On systems that have Pluggable Authentication Modules (PAM) support, all PAM modules are supported. The behavior is just as it was with Samba-2.2.x, and the protocol limitations imposed by MS Windows clients apply likewise. Please refer to Section 10.2 for more information regarding the limitations of Plain Text password usage.
smbpasswd ” This option allows continued use of the smbpasswd file that maintains a plain ASCII (text) layout that includes the MS Windows LanMan and NT encrypted passwords as well as a field that stores some account information. This form of password backend does not store any of the MS Windows NT/200x SAM (Security Account Manager) information required to provide the extended controls that are needed for more comprehensive interoperation with MS Windows NT4/200x servers.
ldapsam_compat (Samba-2.2 LDAP Compatibility) ” There is a password backend option that allows continued operation with an existing OpenLDAP backend that uses the Samba-2.2.x LDAP schema extension. This option is provided primarily as a migration tool, although there is no reason to force migration at this time. This tool will eventually be deprecated.
Samba-3 introduces a number of new password backend capabilities.
10.1.2 New Backends
tdbsam ” This backend provides a rich database backend for local servers. This backend is not suitable for multiple Domain Controllers (i.e., PDC + one or more BDC) installations.
The tdbsam password backend stores the old smbpasswd information plus the extended MS Windows NT / 200x SAM information into a binary format TDB (trivial database) file. The inclusion of the extended information makes it possible for Samba-3 to implement the same account and system access controls that are possible with MS Windows NT4/200x-based systems.
The inclusion of the tdbsam capability is a direct response to user requests to allow simple site operation without the overhead of the complexities of running OpenLDAP. It is recommended to use this only for sites that have fewer than 250 users. For larger sites or implementations , the use of OpenLDAP or of Active Directory integration is strongly recommended.
ldapsam ” This provides a rich directory backend for distributed account installation.
Samba-3 has a new and extended LDAP implementation that requires configuration of OpenLDAP with a new format Samba schema. The new format schema file is included in the examples/LDAP directory of the Samba distribution.
The new LDAP implementation significantly expands the control abilities that were possible with prior versions of Samba. It is now possible to specify " per user " profile settings, home directories, account access controls, and much more. Corporate sites will see that the Samba Team has listened to their requests both for capability and to allow greater scalability.
mysqlsam (MySQL based backend) ” It is expected that the MySQL-based SAM will be very popular in some corners. This database backend will be of considerable interest to sites that want to leverage existing MySQL technology.
xmlsam (XML based datafile) ” Allows the account and password data to be stored in an XML format data file. This backend cannot be used for normal operation, it can only be used in conjunction with pdbedit 's pdb2pdb functionality. The DTD that is used might be subject to changes in the future.
The xmlsam option can be useful for account migration between database backends or backups . Use of this tool will allow the data to be edited before migration into another backend format.