MongoDB DBA Associate case studies
MongoDB DBA Associate · Put your knowledge to work in context.
The MongoDB DBA Associate credential is an entry-to-mid-level certification aimed at administrators who already operate MongoDB in development or small production environments and want independent verification of their operational skills. It suits system administrators, DevOps engineers, and backend developers who have moved from writing queries to running clusters: installing and configuring mongod, planning replica sets, reasoning about shard keys, managing users and TLS, taking and testing backups, and reading server diagnostics. The MongoDB DBA Associate case studies are 5 cases and about 4,637 words.
1Three Members, Two Availability Zones, One Tight Budget
A five-person platform team is deploying a new replica set for an order-management service. Budget allows three VMs: two in us-east-1a (8 vCPU, 64 GB RAM, local NVMe) and one in us-east-1b (2 vCPU, 16 GB RAM, EBS gp3).
847 words, about 4 min2Priority 10, Eight-Millisecond Disks, and a Stale Delayed Member
A five-member replica set (three voting data-bearing members, one priority-0 member in a second region, one hidden delayed member with slaveDelay 3600) serves a ticketing system. Last month an operator set priority: 10 on node B, a 32 GB host with network-attached storage whose fsync latency is 8 ms, versus 0.1 ms on the NVMe hosts.
936 words, about 5 min3The Monotonic Shard Key and the Frankfurt Requirement
A logistics platform shards a 2.1 TB events collection across four shards. The shard key is {createdAt: 1}.
940 words, about 5 min4Turning On Authentication and TLS Without Taking the Platform Down
An audit finds that a six-node deployment - a three-member operational replica set plus a three-member reporting replica set - accepts unauthenticated connections, has no TLS anywhere, and gives all 60 microservices the same root-equivalent user. Fourteen databases are hosted.
939 words, about 5 min5An Eleven-Hour Dump, a Dropped Collection, and a Four-Hour RTO
An e-commerce platform runs a sharded cluster: three shards, each a three-member replica set, plus a three-member config server replica set. Total data is 4.2 TB and the oplog window is five hours at peak.
975 words, about 5 min