From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:57610 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753475AbcBJLN7 (ORCPT ); Wed, 10 Feb 2016 06:13:59 -0500 Date: Wed, 10 Feb 2016 12:14:14 +0100 From: Jan Kara To: Andiry Xu Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, andiry@gmail.com Subject: Re: [Lsf-pc] [LSF/MM ATTEND] [LSF/MM TOPIC] NOVA: A log-structured file system for NVM Message-ID: <20160210111414.GF12245@quack.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 SUSE Labs, CR