blu4 Posted March 13, 2015 Posted March 13, 2015 Hi, I just need clarification on one thing regarding domain controllers. I googled but no clear results came up. Am I correct in understanding that if you have two Domain Controllers on the same subnet, if one fails, the other automatically takes over?
fairm010 Posted March 13, 2015 Posted March 13, 2015 They share the load equally. So if one fails, the other will just pick up its work yes. We have 3 here, 2 on VM's and one Physical. 1
DavePa Posted March 13, 2015 Posted March 13, 2015 As fairm010 says, the load is shared between them and you will find clients authenticating to both of them. DNS is also replicated but if you run DHCP on your DC then that is not - you would need to configure another DHCP server. Also, if one fails and it holds any FSMO roles you should consider moving them to the remaining DC. If your DCs are virtual machines it is probably best to stagger the startup to ensure that they start before any other servers. Finally, any HyperV hosts should not be domain members if you are using VMs for DCs
blu4 Posted March 13, 2015 Author Posted March 13, 2015 Make sure you check where your FSMO roles are! Can you provide a link to a useful explanation for this? As fairm010 says, the load is shared between them and you will find clients authenticating to both of them. DNS is also replicated but if you run DHCP on your DC then that is not - you would need to configure another DHCP server. Also, if one fails and it holds any FSMO roles you should consider moving them to the remaining DC. If your DCs are virtual machines it is probably best to stagger the startup to ensure that they start before any other servers. Finally, any HyperV hosts should not be domain members if you are using VMs for DCs We are doing one virtual DC and one phycical. Does that mean I can add the virtual hosts to the domain?
Geoff Posted March 13, 2015 Posted March 13, 2015 Active Directory FSMO Roles — University Information Services (Academic & Infrastructure)
JRowley Posted March 13, 2015 Posted March 13, 2015 We are doing one virtual DC and one phycical. Does that mean I can add the virtual hosts to the domain? This probably still isn't recommended, in the event of both DCs failing you will have made life very hard for yourself. The likelihood of that happening is probably quite low however.
blu4 Posted March 13, 2015 Author Posted March 13, 2015 This probably still isn't recommended, in the event of both DCs failing you will have made life very hard for yourself. The likelihood of that happening is probably quite low however. We have a second virtual host with AD just in case So that totals to 2 active DCs (one physical one virtual) and one standby.
Firefox Posted March 13, 2015 Posted March 13, 2015 The work is equally shared as long as.... A) They are in the same domain B) They both are DNS servers and are authoritative for the same zones C) Clients are set to look at both DC's for DNS D) Both are Global Catalogue servers E) DHCP is hosted elsewhere, or you have DHCP failover configured (works well on Windows Server 2012R2) FSMO role placement is important...but from a purely urgent need for a working solution not critical (roles can be seized if required)
Davit2005 Posted March 13, 2015 Posted March 13, 2015 (edited) Guide for FSMO roll placement FSMO placement and optimization on Active Directory domain controllers Edited March 13, 2015 by Davit2005
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