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Two exchange servers, one DAG, file server witness question

Can I designate one of our domain controllers at the file witness server (it will be kept at a different physical location that either of the two exchange servers), or is there anything preventing a domain controller from fulfilling the file witness role??

Basically our two exchange servers will be at two separate physical locations, both are running hub transport, client access roles, and at a third physical location I figured I would put the file witness server, just wondering if there is a problem with assigning that to a domain controller.
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Yes you can make you DC as file share witness. But there will be lots of issue if any link goes down between servers as you have all three server in different physical locations.  
Exchange Server will not be able to sync with ad
or DAG quorum issues etc. there could be split brain syndrome situation also.
So it will be better to have DC in all the physical location either you can put them on same site or different sites.
You can use any server as a witness server at location.
Keeping a witness server in different location from exchange servers is a bad configurtion.
Also DAC can be used for split brain syndrome situation.
You can use your DC as a witness server.
But i prefered to use the CAS &HUB Server for Whitness Share,
because this server musst still be online to use exchange and
its the bether way



Ok, well each exchange server will also have a DC at its physical location also, I just figured it made more sense to have the file witness on a DC that isn't at the same location as one of the Exchange servers - the reason for this is if the physical site with the file witness and exhange box loses power, then the file witness wouldn't be able to talk to the other exhange server which would break mail flow anyway.

Is this incorrect?  Meaning, if the site with the exchange server and file witness went down, would it be possible for the other exchange server to take over?

thanks for your question.
I would not use an third location for withness share, because, you
can get a lot of sync - traffic and whitness - file get corrupted and so son..
when your location with witness share an database get down, you have
manuel switch to the second database. But when your location goes down....
user will have no access to ???
Madan SharmaConsultant

Before taking over other exchange server would like to talk with file share witness first to maintain the majority of quorum . If it will not able maintain the majority of DAG then it will not take place to make it work you must have to insert a new or we can say alternate file share witness with another exchange to make it work.
check following 3 part article series for complete details:-


Thanks denisio, actually the users are not at the physical locations that the exhange servers reside.  Basically one exchange server and one DC controller on each coast will go in a separte physical location with an extremely high amount of bandwidth.  All users will basically be connecting to the servers remotely.

My concern was just what would happen if the one site that had the exchange server and file witness went down, how would outlook know to point users at the other exchange server - but from your reply it looks like we would just hav to manaully switch to the second database?


no... you have only to bring the database online on the second server.
manualy...but remember - split-brain - possible
remember -- users find the database over cas-array.
or you can use - realy the following article series for complete details:-
bye and good luck