Bottlenecks

The two biggest performance issues when comparing Samba 4 and a Samba classic domain are network drives and the domain controller. Samba 4 can boost performance of network drives because it supports SMB 3, which Microsoft launched with Windows 8 and Windows Server 2012.

As a domain controller, Samba 4 tends to be worse in terms of data throughput. Practical experience shows that the built-in LDAP server does not compare well with OpenLDAP. But a slower LDAP server only really causes problems when different services use the LDAP connection – and not only to authenticate. This issue can cause bottlenecks if admins also operate DHCP servers, groupware, and mailing lists derived from LDAP.

Samba 4 is also much more memory-hungry than its predecessor. This is especially noticeable when many users are loading the network drives. Admins need to provide enough RAM to maintain a consistent level of performance.

NetBIOS and Browsing

Samba 4 still does not support NetBIOS browsing on the Samba 4 domain controller. Windows clients do not see the domain controller in their network environment. In other words, if Samba 4 is defined as the NetBIOS master, no network devices appear in the network neighborhood.

Many versions of Microsoft Exchange require an LDAP feature that is still lacking in the Samba 4 LDAP, so at this time, it is only possible to add a Microsoft Exchange 2010 system on a Microsoft Server 2008 R2 to the Samba 4 domain.

As is often the case, the Samba 4 environment has several minor stumbling blocks that only stop the show in specific cases. See the Samba bug tracker [9] for details.

Choices

The first important thing is to choose a suitable version of Samba. Although it has been possible to use the Active Directory domain controller in Samba 4 since version 4.0, only version 4.3 promises comparatively little trouble. If you are shopping for a distribution, you should consider Debian Jessie, which incorporates a reasonably current version of Samba, version 4.2.10. But if you also need star and hub replication for multi-site scenarios via KCC, you will need version 4.3. Older versions only allow mesh replication.

Using the Debian Sid development edition will put you closer to the Samba pulse, but a development version is out of the question for many companies. Most other distributions in the enterprise come with rather obsolete packages, including many bugs that more recent versions of Samba 4 fix. If the distribution you use does not come with a current Samba 4 version, admins still have the opportunity to buy packages from Sernet or build from the sources.