AlwaysOn Availability Groups 2016 What is new?

Transcription

1 AlwaysOn Availability Groups 2016 What is new?

2 Patrocinadores

3 SQL Server Discovery Day 25/06

4 Murilo Miranda Database Pythian

5 Agenda About Availability Groups Quick introduction AG news on SQL Server 2016 New capabilities Improvements Better integration with Windows Server 5

6 ABOUT AVAILABILITY GROUPS

7 Quick Introduction to Availability Groups First of all... AlwaysON Not a single feature. It s a marketing term. Two solutions... Failover Cluster Instance Availability Groups 7

8 Quick Introduction to Availability Groups Before AG, we need to talk about Database Mirroring 8

9 Quick Introduction to Availability Groups

10 Quick Introduction to Availability Groups And also about Clustered Instance 10

11 Quick Introduction to Availability Groups

12 Quick Introduction to Availability Groups Finally Availability Groups 12

13 Quick Introduction to Availability Groups Improvements AlwaysON AG Local storage Automatic failover Listener Multiple replicas

14 Quick Introduction to Availability Groups AlwaysON Availability Groups Introduced on SQL Server 2012 Improved on SQL Server 2014 Even better on SQL Server 2016 Future DB Mirroring substitute Based on Failover Cluster Supports 4 replicas Readable secondaries Listener support No shared storage required Enterprise feature Improved availability of readable secondary Increased # of replicas to 8 Better diagnostics Azure Replica support Enterprise feature 14

15 Quick Introduction to Availability Groups Synchronous Asynchronous Readable Secondary Non-Readable (DR)

16 LISTENER LISTENER LISTENER Quick Introduction to Availability Groups

17 Quick Introduction to Availability Groups Let s talk about Improvements! 17

18 Improvements AUTOMATIC FAILOVER TARGETS

19 Automatic Failover Targets Currently we have the option of having 1 failover target and 2 synchronous replicas. SQL Server 2016: +1 Synchronous Replica # failover targets = # of synchronous replicas Total: 3 Synchronous replicas = 3 auto-failover targets

20 Automatic Failover Targets SQL Server

21 Improvements CLUSTER FLEXIBILITY

22 Cluster Flexibility One of the most claimed capabilities is now possible. A domain is not a requirement for AG Windows Server 2016 is required. Three possible variations are: Single-domain Clusters All nodes joined to the same domain Multi-domain Clusters: Nodes are members of different domains AD-detached Clusters Nodes aren t joined to a domain. Workgroup member servers.

23 Cluster Flexibility With this, we are able to build the following scenarios using Availability Groups: Cross domains with or without trust. No domain at all. Nothing changes in the SQL Server management point of view. But administration will be more complex.

24 Cluster Flexibility Active Directory-Detached Cluster Multi-Domain Cluster London Lisbon London Lisbon CLUSTER CLUSTER WORKGROUP Domain A Domain B

25 Cluster Flexibility Cloud Witness recommended London Lisbon Domain A Domain B

26 Improvements DATABASE LEVEL FAILOVER

27 DB Level Failover Triggers On SQL Server 2012/2014 A failover is triggered based on the instance health Even with a database offline, no failover if the instance is marked as healthy. On SQL Server 2016 New option: In case of an offline database, a failover will be triggered. This is not the default behavior.

28 Improvements LOAD BALANCING

29 LISTENER Load Balancing The read-only route is already present on SQL Server 2014 On SQL Server 2016 this list is used to choose a replica and balance the read-only load. Based on a round-robin algorithm SQL Server 2012/2014 READ_ONLY_ROUTING_LIST=( server1, server2, server3, server4 )

30 Load Balancing The base syntax is the same as the one used to define the Read-only route. Examples: Connect in sequence: server1, server2, server3 and server4 READ_ONLY_ROUTING_LIST=( server1, server2, server3, server4 ) Connect in sequence to server1 and server2. If both are unavailable go to server3 and server4. READ_ONLY_ROUTING_LIST=(( server1, server2 ), server3, server4 )

31 Load Balancing This is useful for multi-subnet architectures. READ_ONLY_ROUTING_LIST=(( server1, server2 ), server3, server4 ) London Lisbon

32 Improvements GROUP MANAGED SERVICE ACCOUNTS

33 Group Managed Service Accounts A GMSA is a domain-scoped service account Automatically managed Password rotation is automatic No need to change it in the instance service properties

34 DEMO

35 Improvements DTC SUPPORT

36 Distributed Transaction Coordinator (DTC) DTC wasn t supported on SQL Server 2012 and 2014 An adoption barrier for some applications This is going to be supported on SQL Server 2016 The current version supports cross-server distributed transactions only Full support is planned for an upcoming Service Pack Windows Server 2016 is required

37 Improvements LOG TRANSPORT

38 Log Transport Improvements The entire log transport pipeline was renewed Most efficient Faster Less costly The Redo Thread was also improved Log records are now coming quicker the Redo Thread had to be improved and is now multi-threaded

39 Log Transport Improvements Improvements for distributed AGs AGs involving multiple data centers A new strategy to improve the log record transfer London Lisbon Forwarder Replica

40 Improvements BASIC AVAILABILITY GROUP (BAG)

41 Basic Availability Groups Availability Groups AlwaysON Basic Advanced Failover Cluster Instance

42 Basic Availability Groups Availability Groups have finally become available in Standard Edition! But there are limitations. Do you remember how the database mirroring works? No readable replicas Only two replicas involved Basic Availability Groups (BAG) Only one database per group, etc. BAG will be always better than DBM... But a little bit more difficult to setup! The underlying engine is the same as the AG

43 Basic Availability Groups The current CTP includes an option to create a Basic Availability Group at the beginning of the AG setup The idea is to have a separate wizard.

44 DEMO

45 Improvements DIRECT SEEDING

46 Direct Seeding

47 Direct Seeding Inspired by Azure Takes advantage of the already existing endpoints Directly transfers and restores the database in the replica Not yet available! The plan is to finalize the feature for SQL Server 2016

48 THANK