AlawaysOn High Availability Group in SQL 2014

  • HI,

    Can anyone tell me what are the requirement for Always High availability Group implementation in Production Servers.

    1) Windows Clusters Needed or not ?

    2) All nodes (Primary and Replica's) need Hardware identical ?

    3) Can we implement Always On HA Group in Primary-Physical-sever and Replica-Virtual-servers ?

    3) can we configure Always on High availability without Windows cluster ?

    4) in Always On HA Group, if primary server is down, would replica servers are up automatically without doing any manual work as SQL2005/2008 clusters ?

    5) I heard that without SAN we can configure Always On HA Group (but not sure whether Identical hardware and windows clusters are needed ?

    Would be appreciate if get answers and also can any one send document for complete step by step setup for Always On HA Group on Win2012 R2 and SQL2014.

  • To answer some of your questions:

    1) Windows Clusters Needed or not ?

    Yes it is required

    2) All nodes (Primary and Replica's) need Hardware identical ?

    Not at all, but the OS and Software need to be the same.

    3) Can we implement Always On HA Group in Primary-Physical-sever and Replica-Virtual-servers ?

    Yes, it can be set up to span virtual and physical machines.

    3) can we configure Always on High availability without Windows cluster ?

    Same as question 1 I'm assuming. No you cannot.

    4) in Always On HA Group, if primary server is down, would replica servers are up automatically without doing any manual work as SQL2005/2008 clusters ?

    Short answer yes. Long answer, it depends. HA groups in sql are created inside the SQL instance; it is possible to have some databases as part of an HA group and some not. each group can be set up with automatic failover if required.

    5) I heard that without SAN we can configure Always On HA Group (but not sure whether Identical hardware and windows clusters are needed ?

    You do not need SAN or shared storage, The only requirements for it are a Windows Cluster, and of course SQL Server Enterprise Edition licenses for each active node.

    Here is an article outlining the process of getting it set up:

  • To add to what's already been said

    sreenubabu.s (6/25/2015)


    1) Windows Clusters Needed or not ?

    Yes, furthermore all nodes must be part of the same Windows Server Failover Cluster

    sreenubabu.s (6/25/2015)


    4) in Always On HA Group, if primary server is down, would replica servers are up automatically without doing any manual work as SQL2005/2008 clusters ?

    Starting SQL server 2014 availability groups were changed so that secondarys would remain available in the event the primary was offline\failed

    sreenubabu.s (6/25/2015)


    can any one send document for complete step by step setup for Always On HA Group on Win2012 R2 and SQL2014.

    Please see my stairway series to HA on this site starting at this link

    http://www.sqlservercentral.com/articles/Failover+Clustered+Instance+(FCI)/107536/[/url]

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Thanks a lot..

    1) For testing before implementing in Production, Can we create Always on High Availability Group with 2 nodes (Active to Passive) on Windows 2012 Hyper-V virtual machines ? we already have Domain Controller.

    2) What are the licenses required, do we need licenses for both nodes (hyper V virtual Machines) for Both

    windows and SQL Servers ?

    3) can we install with Single windows License and Single SQL License on both Nodes (Virtual Machines) ?

  • sreenubabu.s (6/26/2015)


    1) For testing before implementing in Production, Can we create Always on High Availability Group with 2 nodes (Active to Passive) on Windows 2012 Hyper-V virtual machines ? we already have Domain Controller.

    Both nodes must be part of the same windows server failover cluster and will each host a stand alone instance of sql server enterprise edition, this will enable you to put an always on availability group across the 2 instances.

    sreenubabu.s (6/26/2015)


    2) What are the licenses required, do we need licenses for both nodes (hyper V virtual Machines) for Both

    windows and SQL Servers ?

    You'll enterprise edition for sql server and standard edition for windows.

    sreenubabu.s (6/26/2015)


    3) can we install with Single windows License and Single SQL License on both Nodes (Virtual Machines) ?

    That would likely violate the licence agreement

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • sreenubabu.s (6/26/2015)


    3) can we install with Single windows License and Single SQL License on both Nodes (Virtual Machines) ?

    Microsoft licensing will allow you to install a passive failover node with one license. As long as you are not using the node for read-only reporting and there are no active db's on it. You will be within your licensing terms.

    I don't believe the same rules apply to the operating system; you'll need to license each server.

  • Of course licencing the hyperv host CPUs with suitable windows and sql server editions will enable you to run multiple vms without issue.

    If it truly is a test server then either use msdn based media if you have it, or the trial versions which provide 180 days usage.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • There is a feature "Automatic fail-over" in "Always on High Availability Group"

    Do we need another node (3rd node) for Automatic fail-over for AO HA Group ? or can we implement Automatic fail-over with 2 nodes ?

  • You don't need a third server; but you do need some sort of quorum for automatic failover. A fileshare witness is probably the cheapest option. It will, of course need to be on another server somewhere.

    Quorom settings in a windows environment is something you can find a lot of information on very easily; have a look around and try and decide what will work best for you.

    Cheers!

  • sreenubabu.s (6/30/2015)


    There is a feature "Automatic fail-over" in "Always on High Availability Group"

    Do we need another node (3rd node) for Automatic fail-over for AO HA Group ? or can we implement Automatic fail-over with 2 nodes ?

    This is all covered in my stairway series.

    Currently in sql server 2014, only 2 replicas may be configured for auto failover, a maximum of 3 replicas may be configured for synchronous commit mode.

    Synchronous commit is required for auto failover.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Can you please provide Stairways links ?

  • sreenubabu.s (7/2/2015)


    Can you please provide Stairways links ?

    see my first post in this thread on page 1 😉

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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