The Cost of Rehashing: From N to N + 1 Servers, Keys That Move and Why It Is So High
This lesson is part of the course
In this lesson
You add a fifth server to a hash-mod-N pool, recalculate the server of every key, mark the keys that move and compare the share that moves with the minimum that would have been necessary.
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Lessons in this course
- Round Robin: Request Number to Server with MOD, Requests per Server and Uneven Speeds Locked
- Weighted Round Robin: Weights, Expected Shares, a Weighted Cycle and Its Error Locked
- Least Connections: Open Connections per Step, Chosen Server with MIN + MATCH, Finishing Requests Locked
- Hash Mod N: Given Hash Values, Server = MOD(hash, N), Keys per Server and Imbalance Locked
- The Cost of Rehashing: From N to N + 1 Servers, Keys That Move and Why It Is So High Locked
- Consistent Hashing: Servers and Keys on a Ring, Next Server Clockwise and Keys Moved When a Server Joins Locked
- Virtual Nodes: Several Positions per Server, Arcs of the Ring, Load Spread and How Many to Use Locked
- Capacity & Failover: Servers for a Target Utilisation, N + 1, Load After a Failure and a Chart Locked