Multi-Region Database Failover Testing

Hard~16h estimatedTechnologyFinanceHealthcare

PostgreSQL MCP ServerAWS MCP ServerSlack MCP Server

The Challenge

Business Problem

Teams write disaster recovery plans but never test them. When a real outage hits, the failover process has bitrotted and doesn't work as expected.

The Approach

Solution Overview

Connect PostgreSQL, AWS, and Slack MCP Servers to periodically test failover to secondary databases, verify data consistency, and report results.

Step-by-Step

Implementation Steps

Schedule Failover Tests

Set up regular (monthly) automated failover tests during low-traffic windows.

Execute Failover

Switch traffic to the secondary database region and verify all services continue working.

Validate Data

Run data consistency checks between primary and secondary after failover.

async function testFailover() {
  await slack.sendMessage({ channel: '#ops', text: '🔄 Starting scheduled failover test...' });
  const primaryCount = await postgres.query('SELECT count(*) FROM critical_table', [], { host: PRIMARY });
  await aws.updateDNS({ recordName: 'db.internal', value: SECONDARY_HOST });
  await sleep(30000);
  const secondaryCount = await postgres.query('SELECT count(*) FROM critical_table', [], { host: SECONDARY });
  const consistent = primaryCount === secondaryCount;
  await slack.sendMessage({ channel: '#ops', text: `Failover test ${consistent ? '✅ PASSED' : '❌ FAILED'}: Primary=${primaryCount}, Secondary=${secondaryCount}` });
  // Failback
  await aws.updateDNS({ recordName: 'db.internal', value: PRIMARY_HOST });
}

Report and Alert

Generate failover test reports and alert if any tests fail.

Code

Code Examples

typescript

Consistency Checker

async function checkConsistency(tables) {
  const results = [];
  for (const table of tables) {
    const primary = await postgres.query(`SELECT count(*), max(updated_at) FROM ${table}`, [], { host: PRIMARY });
    const secondary = await postgres.query(`SELECT count(*), max(updated_at) FROM ${table}`, [], { host: SECONDARY });
    results.push({ table, consistent: primary.count === secondary.count, lag: primary.max - secondary.max });
  }
  return results;
}

Overview

ComplexityHard

Estimated Time~16 hours

Tools Used

PostgreSQL MCP ServerAWS MCP ServerSlack MCP Server

Industry

TechnologyFinanceHealthcare

ROI Metrics

Time Saved8 hours per test cycle

Cost ReductionProven DR readiness

Efficiency GainMonthly automated validation