Backup Domain Controllers in an era of austerity

[swpmre]

Hi,

 

I've been given the task of rolling out Active Directory and Server 2008 across our multiple education sites. These are small Adult Education centres.

 

At the moment, these use a minimum of network resources. We have a Win 2008 server at on site which hosts the shared folders and does the backups.

 

At the same site, I'll be introducing a AD server. However this will create a single point of failure. Loosing connection to this site means that all the remote sites will loose their ability to contact the Domain Controller. So I want to put in at least one, maybe two secondary DCs at the various sites.

 

However we don't have money for any extra servers...... So. The Million Dollar Question is, is there any reason why I couldn't install Win SErver 2008 on an ordinary PC and use that as a backup DC? The minimum spec is certainly fine. But anyother reason why not?

 

I'd value your thoughts.

 

Thanks for your help!

[MatthewL]

There isn't an issue with this. We did this for a while when I first started here due to a DC failing.

 

As long as the machine can run the OS there isn't really a reason. Really you want proper server hardware, you can pick up a cheap server for a DC the same price as a PC these days.

[swpmre]

Thanks matt. Unfortunately we're not buying new hardware at all. But we've got a stock of decent old PCs. This will have to do until the recession ends. Or the economy collapses further, in which case we'll all be living by bartering twigs and it won't matter anymore.

[Jamman960]

Server hardware is generally more hard wearing and designed for 24/7/365 uptime, Desktops are fine for the task but you will be more susceptible to component failure.

[SYNACK]

Yeap, you should be fine just putting it on a standard machine, I would suggest using RODCs at the remote sites to cut down on the possibility of corruption/tampering and lowering the bndwidth requirements a bit.

[unixman]

It all the years that I've been running Microsoft networks (up to 2000 users), I've never bothered with a backup DC and guess what? I've never encountered a problem, even when the PDC has died. I guess if I got near 10,000 users I might add another DC.

 

The worse situation I inherited was a DC which was also the file server. (This was at a well known niche retail company.) I managed to convince the board to purchase a separate file server, which was very lucky, as we had a major disk crash on the DC soon after the file server went live.

[zag]

Both my DC's are on standard workstation machines. Been running 5 years now no problem

[swpmre]

"I've never bothered with a backup DC and guess what? I've never encountered a problem, even when the PDC has died."

 

Problem is that all our sites have connections that have been known to die. So the site were the PDC is likely to be sited has fallen off the network a couple of times in the last year for a day or so. It's because we use cachepilots and they're not the most reliable pieces of kit tbh. So having a backup, somewhere else on the network is a sensible choice for us.

[Michael]

Windows Server 2003 or 2008 can be installed on the oldest of hardware. I would try and stick to a minimum of 2GB of memory however, bearing in mind you'll have AD, DNS, DHCP and Print services to name a few. You could also look into software RAID - I wouldn't recommend it, but it's free!

 

When you have remote sites, maybe connected via a DSL line (for example), it's important to have a DC at each site. This minimises traffic down the single line and also adds redundancy, as failure of the link would mean no one could logon.

 

If everything was on one physical site, maybe connected via fiber links, then I suppose you need to work out the probability of the link going down and whether a secondary DC is worth the additional work.

[CyberNerd]

If your really skint then use a couple of Linux domain controllers in NT mode, save on CALs as well