Redmond Protocols Plugfest 2016 Kevin Farlee Senior Program Manager SQL Server AlwaysOn in SQL Server 2016

How we develop SQL Cloud-first but not Cloud Only Using Azure SQL DB to improve core SQL Server features & cadence Many interesting and compelling on-premises  Cloud scenarios

Unified, simplified solution Easy to deploy, manage, and monitor  Allows using HA hardware resources  Fast, transparent failover  Detects failures reliably  Able to handle multiple failures Mission-Critical Availability

 Server failover  Useful in consolidation scenarios  Shared Storage (SAN / SMB)  Failover takes minutes  Multi-Node Clustering  Passive secondary nodes  Multi-database Failover  Direct attached storage  Failover takes seconds  Multiple Secondaries  Active Secondaries Failover Cluster Instances for servers Availability Groups for groups of databases Availability Groups for groups of databases

Availability Groups Introduced in SQL Server 2012  Multi-database Failover  Multiple secondaries  Sync / Async  Compression & Encryption  Manual/Automatic Failover  Flexible Failover Policy  Automatic Page Repair  Seamless App Connectivity  Configuration Wizard  Monitoring Dashboard  Diagnostics infrastructure  System Center integration  Full cross-feature support  Contained Databases, FileStream, FileTable, Service Broker, In- memory OLTP  Active Secondaries  Read workloads  Backups  PowerShell Automation  Fast Failover Integrated Efficient

An Availability Group Deployment Sync Log Synchronization Async Log Synchronization

HA At Cloud Scale

If you had a reference account with: 1.5 Million Databases across 16 Geographic regions processing 2.5 billion logins per week with 99.99% aggregate uptime Would it help you convince customers?

That’s what SQL Database accomplishes with this technology every day.

Challenges and Solutions

Challenge: Cumbersome to set up Setting up new replicas is cumbersome. Need to set up a file share and grant access Backup to the file share from Primary Restore (with no recovery!) from share to new secondary… How does Azure do this??

Automatic Seeding

Challenge: Wide area AGs are a pain. Commonly used for DR or data locality Quorum issues can shut down DR site Transient Network issues can disrupt availability Multiple replication streams wastes bandwidth

Distributed Availability Groups Intended for remote locations Resolves quorum issues between sites Improves WAN network efficiency Enables mixed Windows versions

Availability Group

Distributed Availability Group

Enterprise Scale

Log Transport Performance New hardware pushes boundaries Very high transaction rates have caused problems when coupled with fast hardware (i.e. PCI-E Flash storage) Re-worked the entire pipeline, end to end. Result is much lower CPU consumption, and much better performance. The bar we’re using is not % better than SQL2014. The bar is how close we are to the perf of a standalone server.

Database-level failover trigger Currently, AG health only monitors the health of the instance. A database can be offline or corrupt, but as long as the instance itself is healthy, we won’t trigger a failover will allow you to optionally change the health monitoring to also consider the health of the databases in the AG. Databases going offline trigger a change in the health status

Challenge: Can’t spread load across multiple secondaries. May have up to 2 sync secondaries, and 5 more async secondaries. Only one of them will get all read-only connections. Other nodes sit idle

Load Balancing in Readable Secondaries In SQL 2014, read-only transactions routed by the Listener, went to the first secondary that was available. Read-only Routing lists Now you can configure the ROR lists to round-robin among a specific set of secondaries. (for each primary)

Readable Secondary load balancing Primary Site DR Site Computer2 Computer3 Computer4 Computer5 Computer1 (Primary) READ_ONLY_ROUTING_LIST= ( (‘COMPUTER2’,’COMPUTER3’,’COMPUTER4’),’COMPUTER5’)

Challenge Service Password Maintenance SQL Service (sqlsrvr.exe) often needs permissions off-box. Common solution is using a domain account Security threat Maintenance nightmare

GMSA Support Group Managed Service Accounts (GMSA) Domain-scoped automatically managed service accounts Automatic password rotation Much more secure than regular domain accounts Enables cross system security context Why would I want a GMSA? How does it work? What versions will it be supported in?

DTC Support Currently, any distributed transactions touching a database in an availability group are not allowed. Many customers run unsupported, at risk to their data and our reputation Lots of Enterprise applications need cross database transactions. Partially Supported in 2016 Joint effort with Windows, requires specific patch in order to work cleanly 2016 RTM only supports distributed transactions where no two databases are hosted by the same instance

Challenge: Continued Availability SQL 2014 has 2 Auto-Failover targets If Primary goes down, there is no automatic failover possible. Can result in loss of availability due to manual failover

>2 Auto-Failover targets Increasing the scale of the solution Increasing resiliency Now any sync secondary can be a target for automatic failover Total of 3 auto-failover targets

Business Challenge: Single Domain Customers may have multiple domains: Bank mergers Multinational corporations Customer may not use AD for authentication at all

Domain-Independent Availability Groups New feature in Windows Server 2016 Environments supported Cross domains (with trust) Cross domains (no trust) No domain at all Cluster management via PowerShell only SQL management as normal Uses certificate-secured endpoints like DBM

Challenge: HA without Enterprise Edition Difficult to move off STD Edition/Database Mirroring configuration Customers unwilling to pay the Enterprise cost differential just for DBM – Always On

Basic Availability Groups on Standard Enables replacement of Database Mirroring by not requiring expensive EE license Limits mostly match DBM: Two replicas Sync or Async No Readable Secondaries No backup on secondary

Redmond Protocols Plugfest 2016 Questions or Comments?

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