Vault 2016

Fast non-volatile memories (NVMs) present challenges to
file system designers. Existing file systems built for HDD
and SSD introduce software overheads that would obscure
the performance that NVMs should provide, but proposed
file systems for NVMs either incur similar overheads or fail
to provide the strong consistency guarantees that applications
require.

NOVA is a file system that adapts conventional
LFS techniques to exploit the NVM characteristics
and provides strong consistency guarantee. NOVA maintains
separate logs for each inode to improve concurrency, and
stores file data outside the log to minimize log size and reduce
garbage collection costs. NOVA’s logs provide metadata,
data, and mmap atomicity, and put indexes in DRAM to
accelerate search operations. Experimental results show that
NOVA outperforms existing file systems by a wide margin.