Consistent Hashing medium
Virtual Nodes (VNodes) improve data distribution balance. What is a primary negative trade-off of using a very large number of VNodes?
- A It significantly increases the memory footprint of the cluster metadata (Ring Map) that every node and client must maintain.
- B It leads to a dramatic decrease in the hash collision rate, effectively wasting computational resources on redundant calculations.
- C It forces the system to utilize a slower, heavyweight cryptographic hash algorithm like SHA-512 to ensure unique token placement.
- D It strictly limits the maximum cluster size to a hard barrier of 256 physical nodes due to internal addressing limitations.
Answer: A. It significantly increases the memory footprint of the cluster metadata (Ring Map) that every node and client must maintain.
While Virtual Nodes (VNodes) improve balance, they also increase the size of the cluster's metadata. If 1,000 servers each have 500 VNodes, the resulting Ring Map contains 500,000 entries. Storing, searching (even with binary search), and propagating this large map via gossip protocols introduces non-trivial memory and network overhead for all participating members.
One system design question a day, with spaced repetition so the ones you miss come back.
Get the appRelated questions
- In a 'Smart Client' architecture (e.g., modern Cassandra drivers), how does the client find the right node?
- When a new node (Node X) joins the ring, where does it acquire its initial data from?
- Google's Maglev hashing algorithm (used in their Network Load Balancers) differs from standard Consistent Hashing rings. How does it generate the lookup table?
- Virtual Nodes improve balance but increase metadata size (Memory). How does 'Multi-Probe Consistent Hashing' achieve good balance without VNodes?
- In the Chord DHT protocol (a P2P consistent hashing implementation), naive lookups are O(N). How does Chord optimize this to O(log N)?
- Which of these systems is a famous user of Consistent Hashing?