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Failover incidents — sound familiar?

  • ▸ Always-On AG sync replica blocking commits — HADR_SYNC_COMMIT waits piling up at peak load; secondary can't apply log fast enough, primary commit latency 10× normal.
  • ▸ AG Listener routing breaking after failover — Read-only routing config didn't update on promotion; read-only connections keep landing on the new primary, no load balancing happening.
  • ▸ WSFC quorum loss after patching — Lost 1 of 3 nodes; quorum holds. Another goes down for patching → cluster goes offline, all AG primaries unavailable until manual intervention.

JusDB HA consultants own the failover playbook + 15-minute incident SLA. Book an HA architecture review →

Always On AG Specialists

SQL Server High Availability

In short: SQL Server high availability involves Always On Availability Groups (up to 9 replicas, readable secondaries, AG listener), Windows Server Failover Clustering for instance-level protection, log shipping for DR, and Distributed AGs for cross-datacenter geo-redundancy — delivering 99.99% uptime with sub-30-second automatic failover and RPO=0 on synchronous commit.

Design and implement mission-critical SQL Server HA using Always On Availability Groups, Windows Server Failover Clustering, and geo-redundant Distributed AGs. Achieve 99.99% uptime with zero data loss failover.

99.99%
Uptime Achieved
< 30s
Auto Failover RTO
RPO = 0
Synchronous Commit
9 Replicas
SQL Server 2019+

SQL Server HA Solutions We Implement

We select and implement the right HA solution for your RTO, RPO, budget, and infrastructure requirements.

Recommended
Always On Availability Groups
Synchronous and asynchronous replicas with automatic failover, readable secondaries, and AG listener for transparent connection routing.
  • Up to 9 replicas (SQL 2019+)
  • Automatic failover
  • Readable secondaries
  • AG listener setup
Enterprise
Windows Server Failover Cluster
Instance-level HA using WSFC with shared or replicated storage. Protects the entire SQL Server instance and all databases.
  • Instance-level protection
  • Shared storage or Storage Spaces Direct
  • 2 or more nodes
  • Transparent failover
DR
Log Shipping
Asynchronous DR solution using automated log backup and restore. Low cost, easy to implement, works across SQL Server versions.
  • Cross-version support
  • DR for older editions
  • Configurable latency
  • Manual failover
Multi-Site
Distributed Availability Groups
Connect two separate AGs across different data centers for global DR without shared cluster infrastructure.
  • Cross-datacenter DR
  • No shared WSFC
  • Geo-redundancy
  • Independent clusters

How We Deploy Your HA Solution

01

HA Assessment

Review current architecture, RTO/RPO requirements, network topology, storage, and licensing to select the right HA solution.

02

Architecture Design

Design the AG topology — replica placement, synchronous vs asynchronous, listener configuration, and subnet routing.

03

WSFC Setup

Configure Windows Server Failover Cluster — nodes, quorum, network adapters, and cluster validation.

04

AG Deployment

Create and configure the Availability Group — endpoints, replicas, listener, and database join.

05

Failover Testing

Perform planned failovers, validate application reconnection via listener, and document RTO/RPO achieved.

06

Monitoring Setup

Configure AG health dashboard, alerts for replica sync state, failover events, and secondary latency.

HA Design Checklist

Every SQL Server HA deployment we deliver covers these critical areas.

WSFC quorum configuration and witness setup
AG endpoint encryption and port configuration
Listener with multi-subnet failover support
Synchronous vs asynchronous replica selection
Readable secondary configuration for read scale-out
Backup preferences on secondary replicas
Automatic failover conditions and health checks
Distributed Transaction support (MSDTC)
SQL Server Agent job synchronization across replicas
Logins, SQL Agent jobs, and linked servers on secondaries
Database Mail and operator alerts for AG state changes
Application connection string configuration (MultiSubnetFailover=True)

SQL Server HA FAQs

Eliminate Single Points of Failure in Your SQL Server

Get a free HA readiness assessment — we'll review your current setup and recommend the optimal HA architecture for your RTO, RPO, and budget.

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Dedicated remote SQL Server DBAs — 60% cheaper than in-house with proactive monitoring and tuning

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Migrations to / from SQL Server (Azure SQL DB, MI, RDS) with minimal downtime via log shipping and DMA

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