August 9, 2012 at 5:46 am
Hello,
I've been looking at the various redundancy/failover technologies within
SS2008R2 and was wondering which one of the following to use and why or
where one is preferable to another:
* Log Shipping
* Replication
* Database Mirroring
If I recall correctly, mirroring is a new addition since SS2005, so is this
an effective replacement for one or both of the others?
Any advice as to which to use or any experiences relating to using one over
the others would be much appreciated.
Regards
Steve
August 9, 2012 at 5:49 am
Well it all depends on your RTO and RTP as to which to choose and if you want hot, warm or cold standbys.
If you know this information then you can choose between, clustering, replication, logshipping, mirroring.
If you ever plan to go to SQL 2012, mirroring is a depreciated feature, and has been replaced by Always On Availability Groups.
August 9, 2012 at 6:06 am
Hello,
RTO? ... RTP?
OK, this is all a bit new to me, so I apologise for my ignorance. I am studying SQL and trying to get to grips with its various features.
I have two PC's and wanted some pointers to perhaps summarize the various advantages and disadvantages of each technology.
As someone new to SQL Server (coming from a 3GL background) I find the deprication of sometimes long standing facilities a nightmare to try and cater for as far as development is concerned.
ANy further help you might be able to offer would be greatly appreciated.
Regards
Steve
August 9, 2012 at 6:13 am
RTO = Recovery time objective - How long do you have to recover service?
RTP = Recovery time point - How much data can you afford to loose?
If a server dies and you need to have it back online in 5 minutes with minimal data loss your looking at clustering or mirroring.
Typically we use a 3 tier setup.
2 servers in primary data centre, 1 server in secondary data centre.
Between the primary servers we have clustering in place and to the secondary we have logshipping.
This is down to the fact that we would not want to fail over the whole IT systems for one server outage, and the latency between primary and secondary was to much for mirroring.
Our RTP is 15 minutes, so logshipping is setup to run every 15 minutes, and in the event that something should go wrong, our RTO is 4 hours, so we have 4 hours to get service restored.
This link might help you on the right tracks
August 9, 2012 at 6:35 am
Thanks so much for your time helping me with all this.
I will take a look at the link you kindly provided.
If I may ask, seeing as you're using mirroring between your two primary data center servers, will you elect not to upgrade to SS2012 in view of this feature being depricated?
August 9, 2012 at 6:59 am
anthony.green (8/9/2012)
RTO = Recovery time objective - How long do you have to recover service?RTP = Recovery time point - How much data can you afford to loose?
Weird, I always called them
RTO = Recovery Time Objective
and
RPO = Recovery Point Objective
Would be interesting to know which one is more correct or, at least widespread. Since I'm not English nor American I would really like to know and possibily correct myself.
-- Gianluca Sartori
August 9, 2012 at 7:07 am
Yep it is RPO, dont know where I got RTP from, must be a combination of RTO and RPO.
August 9, 2012 at 7:18 am
anthony.green (8/9/2012)
Yep it is RPO, dont know where I got RTP from, must be a combination of RTO and RPO.
Ah, great. Thanks Anthony.
-- Gianluca Sartori
July 27, 2014 at 12:46 pm
MIRRORING feature not depricated in SS2012 instead it is enhanced as Always On
July 27, 2014 at 3:54 pm
prasantiki (7/27/2014)
MIRRORING feature not depricated in SS2012 instead it is enhanced as Always On
Mirroring is deprecated. Availability Groups is a new feature, not a direct upgrade (it's a mix of clustering and mirroring and has limitations that mirroring doesn't), it's Enterprise-only where as Mirroring was Standard and Enterprise.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
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