Distributed Systems & System Design
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10 questions
Clear filtersPartitioning & Distributed Data · Senior
We added one cache server. Why did nearly every key move?Compute actual key movement under modulo 4 to 5, compare stable rings and logical slots, and separate owner mapping from physical migration.
Partitioning & Distributed Data · Staff
We doubled the cache shards. Why did one shard get no relief?Diagnose one hot key versus a hot range or placement imbalance, then distinguish bounded-staleness read distribution from inventory-write authority.
Partitioning & Distributed Data · Staff
The writes are spread evenly. Why does one customer's history need 80 queries?Choose physical placement from point-read and per-tenant ordered scan patterns, then manage whale tenants and the ordering cost of sub-bucketing.
Partitioning & Distributed Data · Principal
The new shard is caught up. Can we send it writes now?Specify online shard migration with snapshot and CDC boundaries, tenant-scoped write fencing, stale-router rejection, and rollback after target writes.
Partitioning & Distributed Data · Staff
One storage node died. Why did the rest of the cluster follow it?Diagnose feedback between lost capacity, replica repair I/O, health checks and rebalancing, then size and prioritize recovery under a durability deadline.
Partitioning & Distributed Data · Senior
The bytes are durable. Why can't the database use this object bucket as its disk?Classify storage by operations, mutation granularity, namespaces and durability contracts.
Partitioning & Distributed Data · Staff
The 200 GB upload finished. Why shouldn't we show the file yet?Separate part acceptance, checksums, completion, conditional catalog publication and cleanup.
Partitioning & Distributed Data · Staff
Three copies cost too much. Will six data shards and three parity shards be safer?Derive redundancy overhead, recovery thresholds, placement risks and repair IO.
Partitioning & Distributed Data · Staff
The backup was written five years ago. How do we know its bytes are still correct?Detect latent corruption using expected checksums, scheduled scrub work and verified reconstruction.
Partitioning & Distributed Data · Principal
The cleanup job deleted the chunks. Why were active files still using them?Protect committed manifests from stale mark-and-sweep decisions, delayed DELETE and ABA.