Business continuity

SQL Server High Availability & Disaster Recovery

Resilient SQL Server architectures that minimize downtime, protect critical data and recover predictably when something goes wrong.

Overview

Unplanned outages, hardware failures, ransomware and data corruption can have significant business impact. AVRIN helps organizations design, implement and manage SQL Server high availability (HA) and disaster recovery (DR) solutions that meet availability, performance and compliance requirements.

Every design starts with two numbers agreed with the business: the recovery point objective (RPO) - how much data you can afford to lose - and the recovery time objective (RTO) - how long you can afford to be down. Those targets drive the choice of technology, the number of replicas, synchronous or asynchronous replication, and the budget.

High availability protects against local failures such as a server or disk failing. Disaster recovery protects against losing a whole site or region. Most critical systems need both, plus backups that are tested regularly and stored where an attacker cannot delete them.

Protected database servers representing resilient SQL Server infrastructure

High availability solutions

Reduce downtime and keep applications running during server or component failures.

  • Always On availability groups (single and multi-subnet), including contained availability groups in SQL Server 2022 and later
  • Basic availability groups for Standard edition
  • Failover cluster instances (FCI) on shared or Storage Spaces Direct storage
  • Readable secondary replicas for reporting and backup offloading
  • Health monitoring, listener configuration and automatic failover
  • On-premises, Azure, AWS and hybrid HA architectures

Disaster recovery solutions

Protect data and recover quickly from regional outages or catastrophic failures.

  • Asynchronous availability group replicas and distributed availability groups across sites
  • SQL Server log shipping for simple, low-cost warm standby
  • Backup and restore strategies with off-site, immutable copies
  • Cross-region DR in Azure or AWS, including the Azure SQL Managed Instance link
  • RPO and RTO definition, documentation and optimization
  • Scheduled DR drills with written results

Choosing the right option

A simplified comparison. Real designs often combine several of these technologies.

SQL Server HA/DR options compared
TechnologyProtectsTypical RPO / RTOEdition notes
Availability groups (synchronous)Databases in a groupZero data loss / seconds to minutesEnterprise; basic AGs (one database, two replicas) in Standard
Availability groups (asynchronous)Databases, across sitesSeconds / minutesEnterprise for full functionality
Failover cluster instanceWhole instanceZero on shared storage / minutesStandard (2 nodes) and Enterprise
Log shippingIndividual databasesMinutes / manual failoverAll editions except Express
Backup & restoreEverything, including ransomware recoveryDepends on backup frequency / hoursAll editions

Our design approach

We follow a structured approach so HA/DR solutions match both technical and business expectations.

  1. Assess

    Business criticality, risk, current architecture and licensing.

  2. Design

    Architecture based on RPO/RTO targets, network latency and budget.

  3. Implement

    Build with minimal downtime, then validate failover end to end.

  4. Document & operate

    Runbooks, knowledge transfer, monitoring and ongoing support.

Business benefits

  • Reduced downtime and business disruption
  • Improved data protection and reliability
  • Scalable, future-ready architectures
  • Evidence for business continuity and audit requirements
  • Peace of mind with expert DBA support

Tip: an HA/DR design that has never been tested should be treated as unproven. We schedule failover and restore tests at least annually - quarterly for critical systems.

Discuss your HA/DR requirements

We can review your current setup, test a failover, and recommend the most cost-effective way to meet your recovery targets.

Request a Consultation or call 562.445.5872