hesela.devNOVA file system
NOVA is a research file system for hybrid DRAM and nonvolatile main memory that maintains a separate persistent log per inode.
The FAST 2016 design keeps file data outside per-inode logs and reconstructs DRAM indexes from persistent metadata. Multi-inode operations use lightweight journaling. Its atomic-mmap maps replica pages and commits them through msync; it is not DAX-mmap. [1]
The later NOVA-Fortis design adds corruption protection but exempts read/write DAX-mapped pages from its always-current checksum/parity guarantee. [2]
Relations
Limitations
- These are historical research designs, not guarantees for every persistent-memory filesystem or current Linux build. [1, 2]
Citations
- Jian Xu and Steven Swanson. NOVA: A Log-structured File System for Hybrid Volatile/Non-volatile Main Memories. FAST 2016, pp. 323-338, sections 3 and 4.5-4.7.
- Jian Xu, Lu Zhang et al. NOVA-Fortis: A Fault-Tolerant Non-Volatile Main Memory File System. SOSP 2017, sections 1 and 4.2-4.3. DOI: 10.1145/3132747.3132761.
Further reading
Sources & caveats
- Primary-source comparison; no prototype execution, power-loss experiment or benchmark replication. See FAST 2016 section 4.5 and SOSP 2017 section 4.3 for the distinct mapping contracts.