question

reuvygroovy avatar image
0 Votes"
reuvygroovy asked reuvygroovy answered

Dag Activation Preference

We have Exchange 2016 and have for a while been relying on the DAG Activation Preference functionality mentioned here


Recently we noticed that the balancing mechanism isn't working, and we have some servers with many DBs, and others with none, where in a working world all servers would have at least one DB.

We tried to manually move one of the "misplaced" DBs to the host with the correct Activation Preference and it worked OK. Before we run the RedistributeActiveDatabases.ps1 script to manually balance the DBs, I wondered if there is a log (text file, event log, etc.) where we can view if the balancing is (or isn't) occurring, and why.

I checked all the commands and everything looks good:
123948-2.png124001-1.png


office-exchange-server-administration
2.png (17.2 KiB)
1.png (19.4 KiB)
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

ZhengqiLou-MSFT avatar image
0 Votes"
ZhengqiLou-MSFT answered

Hi @reuvygroovy ,

Have you ever mount the origin copy such as ex1\db1 back after a failover? Please note that the database copy will not be automatically mounted after the server restarted. Which means if you didn't manually mount ex1\db1, the database db1 will be mounted permanently on another server like ex2, this procress will based on the Best Copy and Server Selection. When more servers down, more databases will be mounted on other servers, obviously it will happen that multiple database copies mounted on one server.

For your question, you could use a script named CollectOverMetrics.ps1 to collect information about the database acvitivies. This uses the Event Viewer to search for the logs related to database mount and failover ect.

Best regards,
Lou


If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

reuvygroovy avatar image
0 Votes"
reuvygroovy answered AndyDavid commented

Hi

The DB is mounted on the Primary/Secondary server. The MailboxDatabaseCopy is healthy. As I wrote, I can even manually move the BD. For Some reason, the DB is moving automatically.

· 1
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

You mean its not moving automatically right?

0 Votes 0 ·
reuvygroovy avatar image
0 Votes"
reuvygroovy answered ZhengqiLou-MSFT commented

yes'r and in the past it did, and to my little to nothing understanding, it should

· 1
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

Hi @reuvygroovy ,

Do you mean the DAG active copy changes without a server crash? Is it something like the servers were running healthly while the database active copy switch to another one at that time?

Could you create a test database and add copies of it, see if this database changed automatically. And does the above script give something useful?

Best regards,
Lou

0 Votes 0 ·
reuvygroovy avatar image
1 Vote"
reuvygroovy answered

Seems like the problem went away.

5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.