storage overhead: erasure coding (EC 4+2) vs triple replication — capacity efficiency at the cost of CPU/RAM and rebuild
1.5x vs 3xobserved
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| As of | 2026-09 |
| Source | Ceph documentation, Erasure code · Erasure-coding overview: three-copy replication is 3x; the illustrated erasure-coded configuration uses 1.5x original storage. |
| Derivation | (k+m)/k = (4+2)/4 = 1.5x raw per usable byte; replication size=3 gives 3x |
| Review | checking…review by 2027-09-29 · slow cadence |
| Recorded changes | last 2026-10-05 · 2 revisions tracked |
| Claim id | storage-overhead-erasure-coding-ec-4-2-vs |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.