#crush-map
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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 HEALTH_WARN: Diagnose and Clear Warnings
A triage order for Ceph HEALTH_WARN covering degraded placement groups, nearfull OSDs, missed deep scrubs, autoscaler alerts and monitor clock skew.
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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.