58% of Engineering Teams Reveal Reliance on Single-AZ for PostgreSQL Production Despite Availability Risks

16 September 2026

More than half of engineering teams surveyed by pgEdge and Foundry rely solely on read replicas and automated failover within a single region for PostgreSQL high availability (HA) in production. Despite increasing demand for database-powered applications and growing cloud outage concerns, 58% of respondents run their PostgreSQL production in single-availability zone (AZ) configurations, exposing their mission-critical workloads to significant availability risks.

The mismatch between production demands and HA strategies

The survey, published in July 2025, reveals a glaring tension between the rising prominence of PostgreSQL in business-critical applications and the reliance on single-region HA strategies. According to the findings, a staggering 91% of organizations using PostgreSQL in production demand no more than 4 minutes of monthly downtime for their database-driven services, with 24% aiming for sub-30-second uptrime.

This expectation of near-perfect availability, however, contrasts sharply with the underlying deployment reality. The survey found that 82% of respondents harbor at least some concerns about a cloud region failure, magnifying the risk exposure posed by the widespread adoption of single-region HA.

A closer look at the numbers

The survey of 300 respondents, conducted by pgEdge in partnership with Foundry, probed the prevalence of high-availability configurations used to protect PostgreSQL production environments. The findings underscore a concerning reliance on single-region resilience patterns.

Mission-critical challenge. A majority (58%) of organizations revealed that their PostgreSQL production databases operate in a single-region, single-AZ model, reliant on read replicas and automated failover for HA. Cloud outages, instance failures, or even routine maintenance can spark extended service disruptions in such setups, a troubling proposition given that 37% of respondents use PostgreSQL for mission-critical applications.

In contrast, only 47% have adopted the enhanced robustness of multi-region, multi-master replication for cross-region HA, and an alarming 5% operate with no discernible HA strategy. When surveyed about the business impact of exceeding database SLA thresholds, 56% reported delayed business operations, 49% cited support spikes, 47% required emergency remediation, and 40% pointed to damage to client trust.

A deeper dive into AWS Single-AZ databases

The survey's findings on the prevalence of single-region HA strategies raise critical points about the true implications of a Single-AZ deployment on PostgreSQL availability.

For instance, consider the typical AWS RDS setup using a Single-AZ instance. In the event of an Availability Zone outage, these databases have no automated failover, leaving the database inaccessible and triggering a recovery that could take minutes to hours, according to an analysis by Perun AU.

Moreover, AWS itself cautions that patching a Single-AZ instance impairs availability, as there is no fallback capacity to sustain operations during maintenance. Automated failover, however, is a built-in feature of Multi-AZ deployments, which switch to standby instances during instance or AZ failure.

Practical considerations

The cost implications of relying on a Single-AZ database go beyond mere convenience. As highlighted in binadox's analysis, such an architecture sets an organization up for significant risks, including:

- Extended outages stemming from the lack of automatic failover

- Potential data loss

- SLA breaches as client expectations for uptime go unmet

Further, as highlighted by AWS, Single-AZ deployments create a single point of failure, concentrating risk in one AZ. Multi-AZ setups, in contrast, distribute availability risks across multiple AZs, furnishing users with a highly-available, automated failover mechanism.

Of course, the preference for Single-AZ deployments is likely driven, in part, by their simplicity and lower cost. These configurations are straightforward to deploy and manage, sidestepping the overhead and complexity of managing multi-master, multi-region replication.

Reassessing your HA strategy

Given the key findings of the pgEdge-Foundry survey and the availability implications of Single-AZ databases, engineering teams should prioritize validating the resilience of their PostgreSQL production databases.

At minimum, this should encompass:

- Verifying the presence of automatic failover mechanisms

- Reviewing recovery objectives for both time and data

- Configuring cross-region HA where SLAs demand it

- Ensuring that routine maintenance and patching do not disrupt production

Moreover, teams should be wary of assuming HA by default, especially in Single-AZ setups. As witnessed in the survey, near-perfect uptime expectations are fast becoming the norm, particularly for mission-critical workloads that can't tolerate even brief database interruptions.

In a hyperscaled, mission-critical context, automated failover, multi-region replication, and robust recovery planning are all critical components in moving beyond a reactive, Single-AZ approach, and proactively safeguarding the production uptime required by today's business applications.