It looks like the Intel Atom may be a reasonable build platform for an ultra-low power domain controller. I am interested to know if anyone else is doing this.
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One item that I find annoying about Microsoft domains, is that Microsoft doesn't want ANYTHING else running on a domain controller. There should not be any other tasks on the domain controller, all it should do is manage the domain database?
Exchange on a DC? Ooooh, don't do that, ruins performance.
Microsoft SQL on a DC? The DC may now be really hard to fix if it breaks.
SCCM on a DC? Don't even think about it.
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So the DC needs its own hardware. And Microsoft says we should have two and maybe three DCs for backup purposes.
Does a DC really need a quad core Xeon with 16 gigs of memory? I have DCs with 2 gigs of memory on five year old Dell servers with 10,000k drives, and they are idle 90% of the time.
Why are we wasting so much energy and resources for a single task domain controller, that worked just fine 10 years ago on a 300 mhz Pentium II file server? Have the operating requirements of a domain controller really gone up by 20 times more, to need a dual core 3 ghz Xeon at minimum?
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It seems reasonable that a modern basic laptop or even an embedded Intel Atom desktop client box is probably good enough for a domain controller, but the real challenge is setting up RAID on an ultra-low power platform like this.
Though I am finding some really unusual products out there to make this work, like ExpressCard to full-size PCI-Express adapters.
PCI-Express is fun in that faster multilane cards like 16x are fully compatible with all lower 8x, 4x and 1x slots, if the slot connector is open on one end to allow the unused card edge to hang out in open space. Higher performance cards will just run slower if fewer lanes are used.
So it is possible to take an ultra-low power embedded Atom motherboard with an ExpressCard slot, and with these adapters, plug a full-size server RAID controller into it, to have RAID with hotspares and battery or flash backed cache and an external collection of SSDs or nearline hard drives.
You'd think there's a loss of performance doing this but apparently not. ExpressCard is a four lane interface (x4) and many server RAID controllers are also four lane, so server-grade RAID has the potential to run at full bandwidth performance connecting to a laptop or embedded motherboard.
It looks feasible to build an ultra-low power 64-bit Intel Atom based domain controller, that has battery backed RAID with hotsparing, via a used Dell PERC 5/i SAS controller purchased on eBay. This controller doesn't need to be in a Dell server to work properly.
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Also I have found that a few manufacturers are venturing into the "embedded server" market, though I have not heard of anyone running a domain controller on these.
SuperMicro has several complete Intel Atom based servers, complete with their own fanless motherboard and a full-size PCI Express slot so no need for unusual adapters.
Though most of these are only one or two drive chassis so it's not easy to have a 3rd hotspare RAID available. Also they only include ICH9R, which is more of a "desktop grade" software RAID without battery / flash cache backup capability.
But the PCI Express slot means a full hardware RAID controller can be easily added without all those weird Express Card adapters.
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Has anyone else been experimenting with this?