Project storage needs for a private Docker registry from image count and retention.
Registry storage is driven by: images × tags × avg_size, reduced by layer deduplication (shared base layers stored once). Formula: storage = images × tags × avgSize × (1 − layerSharing%). Aggressive tag retention policies and shared base images significantly reduce actual storage.
Registry Storage
storage = images × tags × avgSize × (1 − layerSharing%)
Running registry garbage collection removes unreferenced blobs (layers no longer pointed to by any manifest), reclaiming space from deleted tags — without GC, deleted tags still occupy disk.
Keep the last N tags per image (e.g. 10-20) plus any tags matching production release patterns; aggressively prune development/feature-branch tags older than a few days.