On Wed, 2010-07-28 at 01:38 +0200, Christian Stroetmann wrote: > At the 28.07.2010 00:00, Ben Chociej wrote: > > INTRODUCTION: > > > > This patch series adds experimental support for tracking data > > temperature in Btrfs. Essentially, this means maintaining some key > > stats (like number of reads/writes, last read/write time, frequency of > > reads/writes), then distilling those numbers down to a single > > "temperature" value that reflects what data is "hot." > > > > The long-term goal of these patches, as discussed in the Motivation > > section at the end of this message, is to enable Btrfs to perform > > automagic relocation of hot data to fast media like SSD. This goal has > > been motivated by the Project Ideas page on the Btrfs wiki. > > > > Of course, users are warned not to run this code outside of development > > environments. These patches are EXPERIMENTAL, and as such they might > > eat your data and/or memory. > > > > > > MOTIVATION: > > > > The overall goal of enabling hot data relocation to SSD has been > > motivated by the Project Ideas page on the Btrfs wiki at > > https://btrfs.wiki.kernel.org/index.php/Project_ideas. It is hoped that > > this initial patchset will eventually mature into a usable hybrid > > storage feature set for Btrfs. > > > > This is essentially the traditional cache argument: SSD is fast and > > expensive; HDD is cheap but slow. ZFS, for example, can already take > > advantage of SSD caching. Btrfs should also be able to take advantage > > of hybrid storage without any broad, sweeping changes to existing code. > > > > Wouldn't this feature be useful for other file systems as well, so that > a more general and not an only Btrfs related solution is preferable? > Would certainly nice to add this feature to all filesystem, but right now btrfs is the only fs which have multiple device support in itself. Mingming > > With Btrfs's COW approach, an external cache (where data is *moved* to > > SSD, rather than just cached there) makes a lot of sense. Though these > > patches don't enable any relocation yet, they do lay an essential > > foundation for enabling that functionality in the near future. We plan > > to roll out an additional patchset introducing some of the automatic > > migration functionality in the next few weeks. > > > > > > With all the best > Christian Stroetmann > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
