An honest read on whether the deployment survives the next order of magnitude

Overview

A public sector agency was preparing to consolidate several departmental systems onto an existing MongoDB deployment and wanted an independent assessment before committing. AceMQ reviewed the deployment against the projected workload rather than its current one.

Challenge

The cluster had been stable for years at its current scale, which made it hard to tell which of its design choices were sound and which were simply untested. Index coverage, schema shape, replica set member configuration, and backup restore times all needed to be evaluated against a workload several times larger than anything the platform had handled.

Environment

On-premises MongoDB replica sets supporting citizen-facing services with defined data residency requirements.

Approach

AceMQ combined static configuration review with measured evidence: index usage statistics to find indexes nothing queried, explain plans on the top query shapes, and a timed restore from the existing backups to establish real recovery objectives. Findings were ranked by risk against the target workload, with effort estimates attached.

Solution

• Index usage analysis identifying unused indexes carrying write and cache cost, plus missing indexes forcing collection scans
• Explain plan review across the top query shapes with concrete rewrite or index recommendations
• Replica set topology review covering member priorities, voting configuration, write concern, and read preference correctness
• Timed restore test from existing backups to establish actual RTO rather than assumed RTO
• Schema review targeting unbounded arrays, oversized documents, and patterns that degrade at higher volume
• Prioritized remediation roadmap with risk ratings and effort estimates for each finding

Outcome

Technologies