Solved

Exchange 2013 DAG databases failing over nightly

Posted on 2014-09-30
5
1,088 Views
Last Modified: 2014-09-30
Hello All,

I am having some difficulty with my DAG for exchange 2013. Every morning that I come in I find that my databases have moved over to another server automatically.

We have 6 servers on VMshere that takes snapshots nightly.

3 CAS servers in a CAS array
3 mailbox servers with 4 databases each.

I cannot find any reasoning as to why this is occurring nightly other than the snapshots. Unfortunately, I am not familiar with VSphere or the snapshots that are taken nightly, I do not do this task. I am just responsible for the exchange servers.

There is also no reasoning behind which server gets the database that morning. One morning I will find all the B mailboxes on A, the next possibly all the databases from A moved to B. Sometimes I will even see a combination of databases scattered across all three.

Has anyone seen this behavior before? Why is this automatically happening every night? (snapshots?)

Please let me know what information I can provide to assist with troubleshooting this problem.

Many thanks to the experts exchange community.
0
Comment
Question by:nyma11
  • 2
  • 2
5 Comments
 
LVL 13

Expert Comment

by:Andy M
ID: 40352265
I'm not very experienced with VSphere but the database in Exchange 2013 will only automatically failover if the witness server and secondary email server are unable to get a response from the primary exchange server at any point.

If this is happening every night and based on the information provided I suspect that while the snapshot is running it's effectively pausing the exchange server, preventing any connections and resulting in the failover taking place.

First port of call would be to check the event logs on both exchange servers - when a failover takes place it logs it under the application log. That should give you a better idea of what time the failover actually occurs and if there's any other errors/warnings around the same time.
0
 

Author Comment

by:nyma11
ID: 40352273
Morty,

thank you for your prompt response. I can actually see the snapshot times and verify they correlate with the databases failing over.

What is the proper procedure for taking snapshots in VMware on an exchange server?

I do not see the point in taking snapshots of the entire server.

Would it be safe to simply take a snapshot of the passive and lagged databases only? I do not understand why there needs to be a snapshot of the whole server and the active databases as well.

Unless I am missing something, if a failure occurs, we can simply use the passive copy, recreate the server and place them into the recreated server.

Please correct me if I am mistaken.

thanks again for your time.
0
 
LVL 13

Accepted Solution

by:
lciprianionut earned 500 total points
ID: 40352290
Hi. What I believe is happing in your environment is that the new feature called Managed Availability is doing the work.
I would suggest to read more about it to understand how it works and then tweak it for your environment.
http://technet.microsoft.com/en-us/library/dn482056(v=exchg.150).aspx
http://blogs.technet.com/b/ehlro/archive/2014/02/20/exchange-2013-managed-availability-healthset-troubleshooting.aspx
0
 
LVL 13

Expert Comment

by:Andy M
ID: 40352291
Hi Nyma

To be honest I'm not sure on the actual procedure for snapshots as we've never used them in any of the virtualized environments we look after - we generally just use actual backup software to backup the server/exchange database as it gives us greater control over restoring mailboxes in the event of a problem.

Providing the replication between the databases is fine I would assume just take a snapshot of the passive database though personally I would get a second opinion from someone who has more experience with vsphere to make sure.
0
 

Author Comment

by:nyma11
ID: 40352455
I looked at the documentation you provided and everything appears "healthy" any other ideas?
0

Featured Post

Do email signature updates give you a headache?

Do you feel like all of your time is spent managing email signatures? Too busy to visit every user’s desk to make updates? Want high-quality HTML signatures on all devices, including on mobiles and Macs? Then, let Exclaimer solve all your email signature problems today!

Join & Write a Comment

Following basic email etiquette rules will help you write a professional email and achieve a good, lasting impression with your contacts.
This article explains in simple steps how to renew expiring Exchange Server Internal Transport Certificate.
In this video tutorial I show you the main steps to install and configure  a VMware ESXi6.0 server. The video has my comments as text on the screen and you can pause anytime when needed. Hope this will be helpful. Verify that your hardware and BIO…
To add imagery to an HTML email signature, you have two options available to you. You can either add a logo/image by embedding it directly into the signature or hosting it externally and linking to it. The vast majority of email clients display l…

706 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now