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Naren avatar image
Naren asked

Mean time to recovery docs?

Hi everyone need any site for mean time to recovery process for anything like mirroing, logshipping,replication etc... If our bussiness is in any HA(High availability) or wihtout HA also if anything happend how much time to take recovery the data and running the bussiness? Can you please share your ideas with me if anything is happned to our transactional database how we can recover the data with in minimal time?
sql-server-2005dba
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Grant Fritchey answered
Recovery is all about backup. High availability is all about multiple locations and multiple servers and mechanisms to make sure that data is in multiple locations so that if one location goes, the other location is available. These are actually two different problems. The interesting thing is, if you set up HA, you still need to set up backups. You don't get away from backups no matter what. I always suggest going to the business and finding out, for each application, how much down time can be accepted. Then find out how much data can be lost. The answer to both these is always "zero" in the initial conversation, but you need to persevere until you get a good and accurate answer. If that answer is "zero" then you need to spend a lot of money setting up mirroring and building a very sophisticated backup process and this will be extremely expensive. There are no hard set of rules, for "X" downtime do "Y." In general you have to look at the needs of the business and the amount of money you have to spend and then start making choices from there.
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You can look that up in the Books Online. You shouldn't have to modify the connection string for failover. You modify it to show that you're setting up a mirror situation and then the connections are routed to whichever server is online. No other modifications necessary.
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The mirror will come online automatically. That's the whole idea behind it. Just remember, mirroring is set up per database. It's not a server thing. Down time is the amount of time it takes to switch connections... near zero in most circumstances. Your app has to be set up with a connection string so that it takes mirroring into account. Data loss, completely depends on how you program. Let's imagine a incomplete transaction. The server goes offline, that transaction goes away. Does your application know enough to resubmit the transaction? It's not something the database or the database server can handle. It's up to the app. There's a bunch more detail on this. I'm taking a week long class on the 2012 Always On technology at the end of January. I'll know more then.
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That is great explanation .... If I am using mirroring and maintain good backup stratgy then if anything is happend to primary server then how many ways to bring mirror to online? And what is the down time and is there any data lose happend at any situation?
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Thank you....
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While failover the principle to mirror server what are the steps need to follow? And is need to change connection string also?
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