Exchange Server 2016 Management Series Courseware 49. Update database replicas managed by the DAG

Under what circumstances need to update the database copy

An update, also known as a seeding, is the process of adding a mailbox database Copy to another mailbox server in a database availability group (DAG). The newly added copy becomes the baseline database for the passive copy, which will replay the log files copied from the active copy. The seed must be set in the following cases:

1. When you create a passive copy of a database.

You can defer seeding for a new copy of the mailbox database, but eventually each passive database copy must be seeded to be used as a redundant database copy.

2. After any database copy has been defragmented offline. Method of seeding 1. Automatic seed setting

Automatic seeding is performed during database creation to generate a passive copy of the active database on the target mailbox server.

2. Seeding with the Update-mailboxdatabasecopy cmdlet

You can use the Update-mailboxdatabasecopy cmdlet to seed a database copy at any time in the shell.

3. Seeding with the Update Mailbox Database Copy Wizard

You can use the Update Mailbox Database Copy Wizard to seed a database copy at any time in the EAC.
Note: You need to suspend database replication before updating.

After the suspension is complete, you can see the update options.

4. Manually copy the offline database

You can dismount the active copy of the database and copy the database files to the same location on another mailbox server in the same DAG. When you use this method, you experience a service outage because the process requires the database to be dismounted.

Updating a database copy can take a long time to complete, especially if the database being replicated is large or the network latency is severe or the network bandwidth is low. After the seeding process starts, do not close the EAC or the shell before this process is complete. Otherwise, the seed set operation terminates.
You can use the active copy or the most recent passive copy as the source for seeding, seeding the database copy. When seeding from a passive copy, be aware that in the following cases, the seeding operation terminates if a network communication error occurs:

1. Seed sets the state of the source copy to changed when it has failed or failedandsuspended. 2. When the database fails over to another replica.

You can seed multiple database copies at the same time. However, if you are seeding multiple copies at the same time, you can only seed the database files and omit the content index directory. To do this, you can use the Databaseonly parameter together with the Update-mailboxdatabasecopy cmdlet.
If you do not use the Databaseonly parameter when seeding multiple targets from the same source, this task will fail with seedinprogressexception error fe1c6491.

Use the shell to update a mailbox database copy

This example shows how to seed a copy of the database DB1 on MBX1.

Update-MailboxDatabaseCopy -Identity DB1\MBX1

This example shows how to seed a copy of a database DB1 on MBX1 using MBX2 as the source mailbox server for the seed.

Update-MailboxDatabaseCopy -Identity DB1\MBX1 -SourceServer MBX2

This example shows how to seed the copy of the database DB1 on MBX1 without seeding the content index catalog.

Update-MailboxDatabaseCopy -Identity DB1\MBX1 -DatabaseOnly

This example shows how to seed the content index catalog for a copy of a database DB1 on MBX1 without seeding the database file.

Update-MailboxDatabaseCopy -Identity DB1\MBX1 -CatalogOnly

Manually copying an offline database (optional reading)

If circular logging is enabled for the database, you must disable it before continuing. You can disable circular logging for a mailbox database by using Set-mailboxdatabasecmdlet, as shown in this example.

Set-MailboxDatabase DB1 -CircularLoggingEnabled $false

Dismount the database. You can use the Dismount-database cmdlet, as shown in this example.

Dismount-Database DB1 -Confirm $false

Manually copy the database files (database files and all log files) to a second location, such as an external disk drive or a network share.
Mount the database. You can use the Mount-database cmdlet, as shown in this example.

Mount-Database DB1

On the server that hosts the replica, copy the database files from the external drive or network share to the same path as the active database copy. For example, if the active database copy path is D:\DB1\DB1.edb and the log file path is D:\DB1, you can copy the database files to D:\DB1 on the server that will host the replicas.
Add a mailbox database copy by using the Add-mailboxdatabasecopy cmdlet and the seedingpostponed parameter, as shown in this example.

Add-MailboxDatabaseCopy -Identity DB1 -MailboxServer MBX3 -SeedingPostponed

If circular logging is enabled for the database, it is enabled again with the Set-mailboxdatabase cmdlet, as shown in this example.

Set-MailboxDatabase DB1 -CircularLoggingEnabled $true

For more It information, you can also follow the public number below:

Zeng Hung Xin's online classroom, has hung Xin da Lecture hall-51CTO College

Http://edu.51cto.com/lecturer/639838.html

Exchange Server 2016 Management Series Courseware 49. Update database replicas managed by the DAG