Re: [Lsf-pc] [LSF/MM ATTEND] [LSF/MM TOPIC] NOVA: A log-structured file system for NVM

[Jan Kara <jack@suse.cz>]

  Hi,

On Tue 09-02-16 22:15:00, Andiry Xu wrote:
> I would like to attend LSF/MM to present a new file system design for
> non-volatile main memories.

Well, LSF/MM is based more on discussions than presentations. Also a lot of
people from LSF/MM will go to Vault so I don't think presenting at LSF/MM
would make much sense. But we register your attend request.

								Honza

> The goal of NOVA is to provide high performance and strong consistency
> (atomic metadata, data, mmap updates) at the same time.
> 
> Although NOVA is a LFS, as it targets a different memory technology,
> it looks very different from conventional LFS. Some of the key design
> decisions of NOVA include:
> 
> Per-inode log: Each inode has a log, with tail pointer points to the
> latest committed entry. This allows for high concurrency and parallel
> log scanning.
> 
> Log is a linked list: Allows for fine-grained, page-size granularity
> garbage collection. Also, allocating log space is easy since NOVA does
> not need to allocate large, contiguous space for logs.
> 
> Cheap atomicity: To atomically append a log, NOVA simply appends the
> log entry and then updates the log tail pointer. To coordinate updates
> across logs, NOVA appends each log and journal the log tails to update
> all logs atomically. This mechanism has lower overhead than journaling
> (which doubles writes) and shadow paging (which causes cascade
> updates).
> 
> Stores file data outside the log: NOVA appends metadata of writes to
> the log and handles file data in a copy-on-write way. This results in
> a shorter log, and garbage collection is simple and efficient, as NOVA
> never copies data in log cleaning.
> 
> Highly scalable: NOVA has free list, journal and inode table at each
> CPU to avoid global locking and scalability bottlenecks.
> 
> NOVA is available on GitHub:
> 
> https://github.com/NVSL/NOVA
> 
> And the paper of NOVA will appear in FAST 2016. I will also give a
> talk in the Vault conference.
> 
> I'm also interested in any NVM/DAX related topics. Thank you.
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR