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EDIT:Not meaning to be disrespectful to any of the answers, but, the main question was whether rebooting a DC at the beginning of a cycle, then all the other servers, or rebooting it at the end once all the others are back online - is there a reason for doing it either way? I'm still not sure based on current responses.

This will most likely seem like a fairly, maybe even stupid, question, but it's something I have been wondering about. As part of a regular process for clients servers are restarted remotely after patches and every client tends to have a similar order - but there always seems to be a small debate when it comes down to when do you reboot your DC.

For example, 4 servers, 1 DC, 1xExchange, 1xBESX and 1xRandom, lets say it has some CRM software installed, is it best to reboot the DC first, then Exchange, then BESX and so on - or reboot all the servers, then reboot the DC last? -

Perhaps it doesn't matter at all and it's just a case of how you have always done it. Would it change in a Hyper-V environment for example, with a physical DC, 1 VHost with all your servers virtualised on that Host? Rebooting the VHost and Virtual Machines first, then the DC at the end, or vice versa?

Bryan
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PnP
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  • You're responsible for doing Windows updates at a client with one DC? I respectfully suggest that you refuse to continue providing this service until they get a second DC. This protects both you and the client, and it should be presented as protecting the client when informing them. – longneck Jul 23 '12 at 14:20

3 Answers3

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You only have one DC? Get a second DC. Seriously. Promote a file server running on a 486 in the basement if you have to. Stop running with a single DC. Now.

Otherwise, it should be fine to reboot them in any order, as long as things are all up and happily running between rebooting one and the next.

Also, regarding your virtualization queries: Always keep one DC and one DNS server completely physical. That is, unless you're really itching for a headache.

Hyppy
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  • Well - it's not us with the one DC, a client. Either way, the main question was whether rebooting a DC at the beginning of a cycle, then all the other servers, or rebooting it at the end once all the others are back online - is there a reason for doing it either way? – PnP Jul 06 '12 at 20:05
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    `"Also, regarding your virtualization queries: Always keep one DC and one DNS server completely physical. That is, unless you're really itching for a headache."` - Disagree. +1 for the rest of it, but there's really no reason to keep a physical DC around if you're 100% virtual and have more than one piece of hardware doing the virtualization. – MDMarra Jul 06 '12 at 20:22
  • Marra, what are you thoughts on the restart order itself? Sorry, I'm still a little unclear from Hyppy's answer as to my original question. – PnP Jul 06 '12 at 20:27
  • He says it should be fine to reboot them in any order. I agree. – MDMarra Jul 06 '12 at 21:08
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To answer your question directly, the order of reboots does not matter if the servers are configured to use cached credentials and there aren't any errors in the DC's AD log regarding a particular client.

Joel E Salas
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For Exchange, it would absolutely matter. Exchange does NOT like booting without access to a domain controller. It's not just about credentials, Exchange stores most of its configuration in AD and expects it to be available at all times. I wouldn't be surprised ir your Exchange information store would hang on startup if the exchange vm was to boot up before the DC.

As for the question: Windows Server 2012 has this functionality. Windows Server 2008R2 has some options to control "memory priority" which Microsoft says dictates the boot order of machines, but to which extent I'm not sure.

Here's a little video from Aidan Finn describing the Server 2012 functionality: http://www.youtube.com/watch?v=OEGkbXQZn4M

Here is some documentation from Microsoft regarding memory priority in Server 2008R2: http://technet.microsoft.com/en-us/library/cc956120.aspx

Trondh
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