Asynchronous Mirroring And Asynchronous AGs

Tara Kizer contrasts asynchronous database mirroring with asynchronous Availability Groups:

ASYNCHRONOUS DATABASE MIRRORING

For asynchronous Database Mirroring, all we need is two servers: the principal at the primary site and the secondary at the DR site. Setup async mirroring between the two, and you’re done. If the secondary server goes down, production still continues. The transaction log isn’t clearing when the log backups occur because the principal still needs to send those log records to the secondary. As long as you have enough disk space where the transaction log resides to support this until the secondary server comes back online, production still continues. Of course if you run out of disk space, users will start receiving errors. But that can take some time and often times is enough time to get the secondary back online.

Availability Groups are more difficult to implement than database mirroring, but the flipside is that they’re much more powerful.

Related Posts

HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING Wait Type

Chirag Shah explains what the HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING wait type really means: Recently a customer reported an interesting issue, while querying against recently added readable replica, SELECT statement is shown as suspended and session is shown as waiting on HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING […] Upon more investigation, it appeared to be waiting on with a wait type HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING The behavior is by […]

Read More

Read-Scale Availability Groups

Ryan Adams explains how to create a Read-Scale Availability Group: A Read-Scale Availability Group is a Clusterless Availability Group.  It’s sole purpose and design is to scale out a read workload.  More importantly is what it is not.  It is NOT a High Availability or Disaster Recovery solution.  Since this design has no cluster under […]

Read More

Categories

September 2016
MTWTFSS
« Aug Oct »
 1234
567891011
12131415161718
19202122232425
2627282930