November 18, 2008 at 8:40 am
I have to implement Database Mirroring or Log shipping on different server in which one server is located in USA and other in Hongkong..
So, which option is best Log Shiping or Mirroring for best performanence? How can i get benifits as well for both?
pls give me ur recommdation..
November 18, 2008 at 9:51 pm
Means i want to say that Mirroring ort shipping is best for both server which are on individual network..???
November 18, 2008 at 9:55 pm
Paresh Prajapati (11/18/2008)
I have to implement Database Mirroring or Log shipping on different server in which one server is located in USA and other in Hongkong..So, which option is best Log Shiping or Mirroring for best performanence? How can i get benifits as well for both?
pls give me ur recommdation..
You will definitely face a speed issue due to the location of the servers
kshitij kumar
kshitij@krayknot.com
www.krayknot.com
November 18, 2008 at 10:04 pm
November 18, 2008 at 10:40 pm
Hi,
this really depends on what you want to implement, since you have only two servers DB Mirroring would be advisable as you dont have to mirror it to multiple servers. And also When DB mirroring is used in Synchronous mode the mirror database is more up to date than log shipping and also its easier to implement.
this link could be useful:
http://blogs.msdn.com/mikewat/archive/2007/07/28/database-mirroring-and-log-shipping-which-is-better.aspx
and also....
http://technet.microsoft.com/en-us/magazine/cc160992.aspx%5Bu%5D%5B/u%5D
November 18, 2008 at 11:02 pm
Paresh Prajapati (11/18/2008)
But Which is best option if i have to implement???Mirroring or shipping ??
Database mirroring can be simpler to implement. When using its synchronous mode, the mirror database is more up-to-date (with no data loss) than its log shipping counterpart, which is only as good as the last log that has been applied to the secondary.
kshitij kumar
kshitij@krayknot.com
www.krayknot.com
November 18, 2008 at 11:18 pm
Paresh Prajapati (11/18/2008)
I have to implement Database Mirroring or Log shipping on different server in which one server is located in USA and other in Hongkong..So, which option is best Log Shiping or Mirroring for best performanence? How can i get benifits as well for both?
pls give me ur recommdation..
you can also think in Data Publish to another server, see more info on SQL BOL.
November 18, 2008 at 11:48 pm
Hi,
Yes if you want to publish your database level objects you can use Replication(merge) technology, if you want to mirror the database either logshipping or DB mirroring
November 20, 2008 at 7:43 am
What really matters here is: What is the purpose? How busy is the primary database? How much bandwidth are you willing to pay for? My following comments pertain to SQL Server 2005, SP2, Cumulative Hotfix 9.
I've set up log shipping and mirroring on several databases located miles apart, each connected to the public internet through normal (T1 on one end, 5mbps on the other) internet connections. Both the log shipping and the mirroring work fine. I find that the mirroring tools for monitoring status are better than the log shipping tools. There is a mirroring monitor you can run and see status in near real time. With log shipping, you have to be very careful that everything is lined up - I had one parameter wrong, everything appeared to be working, the SA jobs were succeeding, but nothing was getting restored on that particular database. With mirroring, the monitor tool compares both servers and gives you an instant status.
LS allows copies to multiple servers, and can be mere minutes behind if you set the schedule up that way. Mirroring can only copy to one server, but is generally only seconds behind. I would NOT use High Availability mode at this distance, I'd use the High Performance mode to allow for hiccups. We have chosen to go with HPerf mirroring for our warm standby server, and LS to our disaster recovery server.
Also, LS requires a share visible from one machine to the other, so it's one more thing to maintain.
Student of SQL and Golf, Master of Neither
November 20, 2008 at 9:40 pm
November 20, 2008 at 9:47 pm
Paresh Prajapati (11/20/2008)
But i think Mirroring is degrade database performanance than shipping..
As per the locations of your servers, the performance will surely degrade but the purpose for which you are going to adopt mirroring or shipping, mirroring will provide accurate and up-to-date results.
kshitij kumar
kshitij@krayknot.com
www.krayknot.com
November 21, 2008 at 2:13 am
My both server are located in individual location (in in usa and other in Hongkong).so mirroring wirh sync mode will be time consuming to commit in partner server...
November 21, 2008 at 7:24 am
Paresh Prajapati (11/21/2008)
My both server are located in individual location (in in usa and other in Hongkong).so mirroring wirh sync mode will be time consuming to commit in partner server...
Which is exactly why I advised that for such an arrangement, you would use High Performance (non synched writes) rather that High Avail (synched writes).
I have found that the impact on the primary server is negligible with high performance mirroring or log shipping. The impact on the secondary server is much more noticable with log shipping. With LS, all the changes for the databases come over in big clumps and get applied at once. Disk Queue length skyrockets, and other apps/databases on the secondary server are affected. With mirroring, I see almost no performance degradation on the secondary server. Coupled with the latency inherent in LS, the only reason I see to use LS anymore is for directing copies to more than one server or for delaying the copying process to an after hours time frame to save bandwidth during the production day.
Student of SQL and Golf, Master of Neither
November 21, 2008 at 7:29 am
Database mirroring is preferable to log shipping in most cases, although log shipping does have the following advantages:
1. it provides backup files as part of the process
2. multiple secondaries are supported
3. it is possible to introduce a fixed delay when applying logs to allow the secondary to be used for recovering from user error
and i found some adv and disadv :
With Log Shipping:
Data Transfer: T-Logs are backed up and transferred to secondary server
Transactional Consistency: All committed and un-committed are transferred
Server Limitation: Can be applied to multiple stand-by servers
Failover: Manual
Failover Duration: Can take more than 30 mins
Role Change: Role change is manual
Client Re-direction: Manual changes required
With Database Mirroring:
Data Transfer: Individual T-Log records are transferred using TCP endpoints
Transactional Consistency: Only committed transactions are transferred
Server Limitation: Can be applied to only one mirror server
Failover: Automatic
Failover Duration: Failover is fast, sometimes < 3 seconds but not more than 10 seconds
Role Change: Role change is fully automatic
Client Re-direction: Fully automatic as it uses .NET 2.0
so as per this what we can conclude for shipping or mirroring ?
November 21, 2008 at 7:37 am
if using database mirroring be sure the network connection is stable otherwise you could end up with unwanted fail overs. Log shipping would be more preferrable, but it depends on what availability you require on the replicated database
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