June 8, 2018 at 4:23 am
Hi, I am looking into setting up a SQL 2016 AlwaysOn Availability Group consisting of 1 Primary server, 1 on-site secondary server and 1 off-site secondary which will be hosted on Azure with a high-speed internet connection and a secondary line in case one fails.
I would prefer to set up both secondary servers to be synchronous, but am sure that will impact performance with regards to the client app. The question is, how much of a performance degradation will it have? We have around 1,500 simultaneous users.
I would consider asynchronous replication for the Azure secondary, but it would weaken the DR infrastructure, especially if we were to lose our site and so would prefer synchronous. Has anyone set up a similar configuration? Any recommendations?
If we lost the Primary server, I would want to make sure that the remaining secondary was in synchronous mode which leads me to ask... Is it easy to change from synchronous to asynchronous? Could I easily switch modes if it was causing issues or if the Primary went down?
Many thanks for your advice and help.
Regards, Michael
June 11, 2018 at 3:44 am
I'd say all you can do is test it. It's very easy to change a replica from synchronous to asynchronous though- you can do it on the fly.
June 11, 2018 at 4:31 am
Beatrix Kiddo - Monday, June 11, 2018 3:44 AMI'd say all you can do is test it. It's very easy to change a replica from synchronous to asynchronous though- you can do it on the fly.
Thank you Beatrix (love that film!). That is all I need to know!
June 11, 2018 at 10:16 am
Michael Fordham - Friday, June 8, 2018 4:23 AMHi, I am looking into setting up a SQL 2016 AlwaysOn Availability Group consisting of 1 Primary server, 1 on-site secondary server and 1 off-site secondary which will be hosted on Azure with a high-speed internet connection and a secondary line in case one fails.I would prefer to set up both secondary servers to be synchronous, but am sure that will impact performance with regards to the client app. The question is, how much of a performance degradation will it have? We have around 1,500 simultaneous users.
I would consider asynchronous replication for the Azure secondary, but it would weaken the DR infrastructure, especially if we were to lose our site and so would prefer synchronous. Has anyone set up a similar configuration? Any recommendations?
If we lost the Primary server, I would want to make sure that the remaining secondary was in synchronous mode which leads me to ask... Is it easy to change from synchronous to asynchronous? Could I easily switch modes if it was causing issues or if the Primary went down?
Many thanks for your advice and help.
Regards, Michael
Hi Michael
What's a "secondary line in case one fails"?
June 11, 2018 at 11:06 am
AlexSQLForums - Monday, June 11, 2018 10:16 AMHi Michael
What's a "secondary line in case one fails"?
A second internet phone line in case one line goes down...
June 11, 2018 at 2:49 pm
Michael Fordham - Monday, June 11, 2018 11:06 AMAlexSQLForums - Monday, June 11, 2018 10:16 AMHi Michael
What's a "secondary line in case one fails"?A second internet phone line in case one line goes down...
Ok. I guess it depends on your workload and if you really need sync mode for Azure.
Set it up and test it with a tool which can simulate 1500 simultaneous users.
You should also look into read only routing. http://www.sqlservercentral.com/articles/always+on/167193/
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