How Exchange 2010 DAG works in case of server crash in same site

Hi 

I have a setup of 4 exchange 2010 std edition servers with the following scenario I would like to know How DAG works in case of server crash of mailbox server which is holding active copy of database 

2 Mailbox server (configured in DAG)

2 Cas array server (configured with CAS Array + NLB+1 server is FSW)

I had an incident few days back that one line of power is off and we have limited UPS time only 10 mins mailbox servers shutdown improperly it was holding active copy of database as soon as it goes down outlook users get disconnected until power comes back and server starts 

I would like to know how I can shift database copy to another available if this situation occurred again to me  

September 9th, 2013 9:06am

Hi

If one of your mailbox servers shutdown and you still had the other mailbox server running along with both CASs then the database should have failed over automatically and no users should have been affected.  As long as you have 2 votes (1 mailbox server + FSW or both mailbox servers) the cluster should stay online and users will have access to email.

Steve

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September 9th, 2013 9:36am

Hi Steve,

Thanks for your info at the time of power failure the server which has FSW was also down this is may be the case user were unable to connect and send / receive email

can I configure alternate FSW on another server so if in case one FSW goes down other should take care of cluster

Thanks

September 9th, 2013 6:35pm

Hi

OK if your FSW is down along with one of your mailbox servers then your databases will dismount.  Configuring an alternate FSW will not help in this scenario as you only need these when you are manually performing a datacentre switchover: http://blogs.technet.com/b/exchange/archive/2011/05/31/exchange-2010-high-availability-misconceptions-addressed.aspx

Is it not possible to make sure that your FSW will stay online in the event that whatever causes your mailbox server to be offline?

Steve

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September 10th, 2013 6:30am

Thanks but is there any way I can make sure my DAG & FSW will work fine if in case server crash / power failure 

Thanks 

Ehsan 

September 10th, 2013 8:58am

The only way you can be sure of anything is to test.  Take a time out of hours to shut down one of your mailbox servers and see if the databases stay mounted on the other.

Steve

Free Windows Admin Tool Kit Click here and download it now
September 10th, 2013 12:05pm

Thanks again steve for your time and all your replies 

1. but I noticed so many time on my site database shift from one server to another but mostly it is mounted on the server where database is originally not created but server is member of DAG

2. in the above reply you said shutdown the server and see if the database shift from one server to another should I do normal shut down or abnormal shut down and if I do normal shutdown may be services shift from one server to another and If I do abnormal shut down what will be time should I wait to see if database is shifted from one server to another or not

3. if in case database didn't shift manually from one server to another what is manual way to shift the database to available dag member in case of normal / abnormal shut down

Thanks

September 10th, 2013 2:44pm

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