SQL2016 Stretch database. Yes, it’s another linked server
September 17, 2016
Your manager always wants to keep all the data...now with bigdata being a thing and algoritmes are used more efficient (IOT), people want to hoard data even more, but it needs to be online to be valuable. If you have to restore the data first, your data is not very valuable. But all this extra data also slows down your database performance...and gives the dba'ers extra challenges....but not anymore.! Well, at least when your boss got a big wallet and don't mind spending it on a SQL buget.
In SQL2016 Microsoft introduced the stretch database. which give you live access to 'archived' data and makes it feel like it's on premise. And it's a secretly just a linked server! A linked server between mssql and Azure.
How does this work, and is it safe?
Yes! since it works on secure linked server technology and it stores an encryption key on the on-premises sqlserver, it's suitable for all your cold data, not hot, because it does slow down the query speed, but it will not clogg your network and your data will be available at all times, even when the data is being stretched over to Azure the data still is fully query-able.
First ask yourself, Do you really need to keep this data? If yes, How do you create a stretchdatabase? Well, this is easy!
I use a simple test database, the adventureworks2016 ctp3.
Before we can start, check if the data archive function is enabled, if not (0) enable it.
####Check status of Remote data archive#### SELECT @@VERSION AS 'SQL Server Version'; EXEC sp_configure 'remote data archive'; GO ####Activate Remote data archive#### EXEC sp_configure 'remote data archive' , '1'; GO RECONFIGURE; GO
Next we can create a master key to encrypt all your data locally, this way, the data can't be read in Azure.
Note: You can also create a masterkey from the stretchdb wizard, it's up to you. I'll show both options.
USE AdventureWorks2016CTP3; GO CREATE MASTER KEY ENCRYPTION BY PASSWORD='stretchdb2016'; GO
Next I will create a simple table and populate it with some data, to keep the demo quick and simple :
CREATE TABLE dbo.Stretchtable ( FirstName VARCHAR (50), LastName VARCHAR (50) ); GO Use [AdventureWorks2016CTP3] GO INSERT INTO dbo.Stretchtable (FirstName, lastName) VALUES ('Reed', 'Richards'), ('Benjamin', 'Grimm'), ('Sue', 'Storm'), ('Johnny', 'Storm'), ('Victor', 'Von Doom'), ('Willie','Lumpkin'); GO
Keep your Azure account ready! I use the SQL logical server resource, you need to create a resource before you can stretch the database.
Select the table you will be stretching to Azure. Now enable the table for stretching and the wizard will open up.
It's a Hybride archive - You can stretch the whole table or filter out the (c)old data from a massive table.
Next thing you create a master key, if you didn't make it before, if you made it already, It will ask you to fill in the master password.
Fill in the IP range for a firewall rule.
Hey Ho, let's go, that was easy!
Now the table will start to stretch, if you want to see if it stretched yet, try a select query and check the executionplan.
Want your data back? No problem, You can bring back the data to your on-premise server, if you don't want to use Azure. Because, when you delete your azure account, the data will be gone too!
Note: Data storage can be expensive on Azure, but this function gives us a positive view on the ever growing databases and it's possibilities.