databases

Transparent versus explicit hugepages is a control question, not a size question. Fork-heavy stores suffer THP copy-on-write amplification while large-resident databases gain TLB reach.

Database redundancy still needs reconnecting clients. Distinguish the deployment type, then measure how promotion and DNS changes affect application requests.

Volume choice is IO-shape matching: burst buckets, provisioned IOPS and throughput designs behave very differently under mixed OLTP-plus-batch load. Average latency graphs hide the failure entirely.

Ask whether Multi-AZ means a DB instance or a DB cluster. One has a non-readable standby; the other has two readers. That distinction decides whether the proposal can relieve the primary.

Volumes grow online and never shrink; StatefulSet template changes normally replace pods ordinal by ordinal; supported in-place pod resize is a separate path. The craft is expanding storage first, gating rolls with partition, and letting replication lag set the pace.

The default answer is 'horizontal' because interviews reward it. The correct answer names the constraint that makes distribution expensive and knows when one big machine is the engineering choice.

Most migrations are safe and a handful can take the site down by holding a lock for eight seconds. Build the tooling to tell those apart automatically, because a review culture cannot do it two hundred times a month.