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What EC Protection Level is needed?The EC protection level determines how strictly EC segments must be distributed for a write to succeed, or else return an error (412 Precondition Failed) to the writing application. After Swarm writes an object to the cluster, the health processor tries to maintain the requested protection level. If cluster resources become unavailable, it will degrade gracefully. When this occurs, the health processor logs errors, alerting you that the requested protection cannot be maintained and that your data may be at risk. Regardless of the protection level you set, Swarm always makes a best effort to distribute segments as broadly as possible across your hardware, to protect your data. | ec.protectionLevel | Cluster requirements | Effect |
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| subcluster | >= (k+p)/p subclusters | Requires a subcluster for every p segments. Use only if you have geographical or systems-based subclusters defined that you need to factor into content protection. | | node (default) | >= (k+p)/p nodes | Requires a node for every p segments. Use for most situations. Important: When working with a small number of nodes, be sure that your EC encoding can support what you have. - With 3 nodes, you can use
3:2 encoding ((3 + 2) ÷ 2 = 3 nodes required), but not 3:1 encoding ((3 + 1) ÷ 1 = 4 nodes required). - With 4 nodes, you can use
4:2 encoding ((4 + 2) ÷ 2 = 3 nodes required), but not 4:1 encoding ((4 + 1) ÷ 1 = 5 nodes required).
| | volume | >= k+p volumes | Least protection. Requires k+p volumes, but p+1 nodes are still needed because the manifest must be written to separate nodes. Use only if you have insufficient nodes for node-based protection. |
| < k+p volumes | Unsupportable. EC writes will fail. |
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| The setting ec.subclusterLossTolerance has been deprecated and needs to be removed from configurations when upgrading to Swarm 10. |
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Versioning Policy
Swarm has policy support for object versioning, which makes it possible to enable versioning for specific contexts (domains and buckets) after you configure the cluster to permit versioning of objects.
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