It's not the cost of a few domain controllers...it's the $50-60/user cost of client access license (CALS). I have 2500 users...that's quite a pricey (approx. $62K) system for directory services.
If getting AD Domain Services off of Windows will actually avoid the need to buy any Windows Server CALs, then it certainly makes the proposition more interesting. But, this presumes that nearly all the other services (file sharing, http, etc.) are also not Windows.
I have to buy user CALs for #1 and #2. One CAL gives me the right to connect that user to any of our file shares and to AD. IIRC, that cost when we last purchased was around $50/user.
We also have to buy a separate CAL for Exchange.
I would love to replace AD and our Windows file shares with Samba 4, provided that it was a stable, viable replacement which didn't add a lot of overhead for our admins. Exchange is a separate issue, and one we're currently exploring Zimbra as a possibility. It's early days yet there.
Almost everything else in our environment is Linux.
I have to say that Microsoft convincing businesses that they need to pay to connect to servers that they've already paid for is a shear piece of economic genius. Morally abject, but still brilliant financially none the less.
1. I wouldn't need to hire an extra IT person. I already have very capable Linux admins.
2. Bad Windows sysadmins are less expensive than good Linux sysadmins. I agree with you there. Good Windows admins, however, are just as expensive. Trust me...I've hired quite a few.
3. Again, I have well-trained Linux guys on staff.
4. This is a very valid possibility we'll need to consider.
5. Not worried about that at all. We use a lot of open source without commercial support options, and our experience with Microsoft support is four hours of scripted troubleshooting on average, with about a 60% success rate of resolution.
6. Not concerned with this at all. Samba has been here for a long while and I don't think it's going anywhere.
But IT departments are expensive, why can't we just hire kids without college degrees to work minimum wage and make millions of dollars of hardware sing in harmonious chorus? The kids are good with the computers right?
If it potentially could save licensing costs of about one sysadmin it is worth looking at. It is unlikely (but possible) an entire additional sysadmin will need to be employed just to support Samba.
Agreed. We currently have to keep a Windows admin on staff (who actually costs a lot more than the CALs) just to manage our shares, Exchange, and file servers. It'd be nice to get these final pieces of the Windows puzzle out of our environment and staff solely Linux admins.
But I do agree with the dbrain's sentiment. If it was going to have a significantly higher TCO, I wouldn't do it.
There's definitely a benefit for having those "one off" admins around. I'm the one Linux guy surrounded by 4 Windows admins. The services I'm responsible for can easily be pushed on to Windows servers... but I'm kept around for the off chance that some software will only run on Redhat or Citrix or whatever. But I'm also useful in how I approach tasks. My coworkers are quick to search Google for an answer, download a tool and have it do the dirty work. I'd rather look at the documentation, source code or API, raw log files, or even write my own tool to do whatever's necessary. Neither philosophies are wrong. But some are definitely better.
All that being said, I'm also underpaid (80% regional average). Maybe that's the real reason they keep me around.
I personally am going to give Samba 4 a look.