#erasure-coding
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Ceph Erasure Coding vs Replication: How to Choose
How erasure coding and replication differ in space amplification, failure tolerance and write cost, with a k+m overhead table and a rule for picking one.
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Ceph Hardware Requirements: CPU, RAM, Disks, Network
Ceph hardware requirements: 3 hosts for replicated pools; EC needs k+m. Compare 1-4 CPU threads, 4 GiB RAM per OSD, drives, and 10 Gb/s networking.
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How Ceph Places Data: CRUSH, Pools, and Placement Groups
An orientation to Ceph's data placement model, covering OSDs, pools, placement groups, CRUSH failure domains, and replication versus erasure coding.