Pengembangan Immutable Object Storage dengan Concurrent Garbage Collection dan Read-Proxy untuk Mitigasi Ransomware

Abstract

Modern ransomware targets both operational data and backup repositories, while mutable storage can still permit physical deletion through a compromised application. This study develops and evaluates a single-node Immutable Object Storage system based on Content-Addressable Storage (CAS) and FastCDC. Its contribution is an integrated design combining chunk-level deduplication, verified reads without directory access for the public application programming interface (API), and concurrent reclamation that revalidates references and activity before physical deletion. The system separates the public API from Vault Core, derives BLAKE3 chunk identities, and manages manifests and references in BadgerDB. Concurrent Garbage Collection (GC) reclaims unreferenced chunks, while a Read-Proxy over a Unix Domain Socket (UDS) provides the API reading mechanism. A shared Store instance, read leases, an active-upload registry, a grace period, and final validation coordinate reads, uploads, manifest changes, and physical deletion. Unit and race-detector tests, a production-component configuration test, and a UDS performance harness show that principal flows operate as designed, with no errors found in Read-Proxy samples. Four uploads totaling 32 MiB achieved a 96.1961% chunk-reuse ratio and 93.6187% byte savings. With 16 concurrent clients, median Read-Proxy latency was 1108.762 ms. GC reclaimed 2,056,192 bytes, while read throughput decreased by 9.1692% when GC was active. The architecture narrows public API authority, preserves integrity verification, and provides a detection window before physical reclamation. The evaluation is limited to a synthetic dataset, one device, one FastCDC configuration, and at most 16 clients.