> my concerns are around replacing AD Domain Controllers with Samba.
Here for us (not OEM) the whole AD stack you mentioned is completely overkill, and the stuff implemented by this Samba release looks terribly like covering 99% of what we use and need in our half windows (customer TSE access, networked file store), half linux (web hosting + many services) infrastructure.
In my tech environment, 3 cost-driven retailer clients with ~1000 branches have some 3rd party software which requires some AD to be present. Samba 4.x will be a nice option. They will start by migrating some branches from Windows Servers to Linux based AD services and move ahead as they see success.
Most people try to measure the cost benefit of free software, with TCOs, CALs, admin salaries etc. That is fine, but the true benefit of free and open source software in my experience:
1) The absence of license considerations in designing and developing systems; this frees the designer's mind in planning, and building. Now the system components can be planned without fear of a multitude of diverse, artificial license schemes.
2) The absence of a license-selling company; this frees the management's mind in estimating and revising the costs moving ahead. License-sellers like Oracle, Microsoft are well known for figuring out diverse sets of confusing licensing schemes. They spend their money in hiring the best sales people which are famous for hunting and then farming clients in the span of 5-10 years ahead by first locking them down.
Here for us (not OEM) the whole AD stack you mentioned is completely overkill, and the stuff implemented by this Samba release looks terribly like covering 99% of what we use and need in our half windows (customer TSE access, networked file store), half linux (web hosting + many services) infrastructure.