November 16, 2011 at 12:54 pm
We have a DB which is on a cluster. That is currently being log shipped to a DataCenter across the nation to the other coast.
I would like to suggest DB Mirroring for this DB, just so we will have Automatic Failover. But before they cut off Log Shipping -- they would like to see how Mirroring is working.
Question is can I also Mirror the same DB which is currently being Log Shipped ?
November 16, 2011 at 1:29 pm
I got the answer, it is a Yes :hehe:
For more information
November 17, 2011 at 9:31 pm
Automatic failover requires synchronous Mirroring, therefore the mirror should be fairly close to the primary to keep latency low. This is because synch commits each writing transaction on the mirror BEFORE the full transaction is committed and hardened on the primary. Network or other latency between the two systems will cause write performance to plummet from an end user perspective.
Log shipping the same primary db is a great common strategy to add to synch mirroring so that a remote data center (in a different natural disaster zone) offers a semi-near real time copy of the data with no real latency issues. Some choose to delay their log shipping by 1 or 2 hours to allow easier recovery in the event of a Delete with no where clause, without requiring a full blown restore process.
SQL Server 2012 also has a new enterprise edition feature called AlwaysOn which will allow multi synch and also asynch secondaries on the same database. This is sort of what you are accomplishing with the 2 different HADR technologies. AlwaysOn also allows for read only access to the secondary, as well as many other new benefits.
Jim Murphy
http://www.sqlwatchmen.com
@SQLMurph
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