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question about Always on

  • January 13, 2020 at 12:37 pm

    #3714874

    I know there is good feather "Always ON" since SQL Server 2012, but I didn't used it, I have some question about it. thanks!

    1. Is it(always on) the best way to achieve high availability as of now ?
    2. if we use always one, I can't make sure the data and data objects can't be synchronized real-timely, is it right ? yes,  how many seconds is the delay between the two databases ?
    3. is any post to show us how to build always server ?

  • January 13, 2020 at 1:50 pm

    #3714902

    First, AlwaysOn is marketing speak. You want to talk about Availability Groups. That's the technical implementation that you'll be working with. Just knowing that will help all your web searches, let alone your implementation.

    1. Probably, yes. There are some third party tools and hardware specialties that can be better, but in terms of what's offered within SQL Server, yes.
    2. None of the high availability solutions can guarantee completely perfect real-time synchronization. Even simultaneous writes to two databases in two servers are likely to vary. So, there is a lag time. The degree of that lag time completely depends on your system, your network, disks, data size, amount of date, etc., and ad infinitum. You can affect this through all the standard means. Further your choices as to synchronous or asynchronous setups will also affect latency (and load and behavior).
    3. Microsoft has tons of good documentation. I'd go there. Also, the Stairways series here can help.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • January 14, 2020 at 4:16 am

    #3715132

    thank you for you kind help Grant Fritchey !

    Sorry to bother you again ! could you please recommend  1 or 2  third party tool of data synchronization among databases ? thank you!

  • January 14, 2020 at 11:10 am

    #3715181

    You can try something called ‘Double Take that synchronises the selected data at bit level . hope that helps.

     

  • January 14, 2020 at 1:22 pm

    #3715199

    I was thinking more about hardware style solutions. Pure Storage has an internal snapshot mechanism that is fully transactionally aware. It would be worth pursuing, depending on your functional needs. Other vendors have similar solutions. Just search for them.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • January 15, 2020 at 11:58 am

    #3715563

    nice post

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