45Redis warns against transparent hugepages while the DBA asks for 2MB pages. Who is right?▼mediumNewPhonePeRazorpayOracle◆ premiumTransparent 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.Open full answer →
09The database failed over to its Multi-AZ standby and the application fell over anyway. What did Multi-AZ promise, what does it not?▼mediumNewAmazon & AWSRazorpayJPMorgan ChaseunlockedDatabase redundancy still needs reconnecting clients. Distinguish the deployment type, then measure how promotion and DNS changes affect application requests.Open full answer →
15Pick an EBS volume type for a Postgres primary with a nightly analytics batch. What decides it?▼mediumNewAmazon & AWSPhonePeGoldman Sachs○ sign inVolume 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.Open full answer →
16Reads are drowning our database primary. Someone suggested Multi-AZ. Does that help, and if not, what does?▼easyNewRazorpaySwiggyJPMorgan Chase○ sign inAsk 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.Open full answer →
58The database StatefulSet needs more CPU and larger volumes with no downtime. Walk me through volume expansion and the restart choreography.▼mediumNewRazorpayPhonePeSnowflake◆ premiumVolumes 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.Open full answer →
07When would you scale a system vertically rather than horizontally? Give me a case where vertical wins.▼easyNewOracleSAPGoldman SachsunlockedThe 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.Open full answer →