YOUR BRIEF
What to work through
Work through a distributed cache as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Set, get and delete key-value pairs
- Set an expiry time on each key
- Evict the least recently used keys when memory is full
BEFORE YOU START
Constraints to discuss
- Get and set answer in under 10 ms
- Hold 1 TB of data
- Serve 100,000 requests a second at peak
- Highly available; eventual consistency is acceptable
Need a starting point?
Watch for these common gaps as you prepare:
- Placing keys by hash mod N
- Finding the LRU key by scanning or sorting timestamps
- No plan for a hot key
- Promising strong consistency across copies without its cost
- Adding disk durability nobody asked for
Why this question is in the collection
These sources connect the problem to company interview reports or preparation guides. They do not guarantee what a company will ask you.