longhorn: default StorageClass to 2-way replication #196

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aaron merged 1 commit from plane/longhorn-default-2way into live

2026-04-28 02:05:51 +00:00

aaron commented

2026-04-27 23:05:46 +00:00

Owner

Set persistence.defaultClassReplicaCount=2 so the auto-created longhorn StorageClass provisions PVCs at 2-way (matching longhorn-db and defaultSettings.defaultReplicaCount). Single-host topology means 3-way buys nothing real (host failure takes all replicas) while tripling write I/O. Existing 3-way volumes patched in-cluster (6 volumes: minio×2, redis, nats, mapstorage, lab-director-app).

Set `persistence.defaultClassReplicaCount=2` so the auto-created `longhorn` StorageClass provisions PVCs at 2-way (matching `longhorn-db` and `defaultSettings.defaultReplicaCount`). Single-host topology means 3-way buys nothing real (host failure takes all replicas) while tripling write I/O. Existing 3-way volumes patched in-cluster (6 volumes: minio×2, redis, nats, mapstorage, lab-director-app).

aaron added 1 commit

2026-04-27 23:05:46 +00:00

feat(longhorn): default StorageClass to 2-way replication

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6d706258c2

Set persistence.defaultClassReplicaCount=2 so the auto-created `longhorn`
StorageClass provisions PVCs at numberOfReplicas=2, matching `longhorn-db`
and defaultSettings.defaultReplicaCount.

Single Proxmox host topology means Longhorn 3-way replication adds no
cross-host fault tolerance — host failure takes out all 3 VMs and all 3
replicas. The ZFS mirror at the storage layer already handles single-disk
failure, and CNPG B2 backups handle durability. 3-way only triples write
I/O on the shared SSD/HDD pool with no real availability gain.

Existing volumes provisioned before this change remain at 3-way (SC
parameters bind only at provisioning time) — those are migrated separately
by patching their volume.longhorn.io spec.numberOfReplicas in-cluster.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>