On Tue, Mar 5, 2013 at 1:42 PM, Dmitry Smirnov <only...@member.fsf.org> wrote: > On Tue, 5 Mar 2013 13:39:38 Liang Guo wrote: >> JFYI: In linux 3.9-rc1, dm-cache are merged to mainstream kernel, > > Interesting, thank you. > You're talking about https://github.com/mingzhao/dm-cache > right? > > I've seen it but couldn't figure out how to use it... > Nice to have it merged though even if it is not immediately useful... > I think the answer is No. mingzhao implemented dm-cache several yeas ago, it was used to accelerate cd-rom or nfs access by using hard disk. but had never been merged to upstream kernel. Several yeas later, facebook created flashcache based on mingzhao's dm-cache when SSD becomes popular, then STEC, Inc created enahnceIO based on flashcache.
DM-cache merged to upstream kernel in 3.9-rc1 is not the one wrote by mingzhao, but from RedHat, I don't know whether it has any relation with mingzhao's dm-cache. Its documents can be found at [1][2], the original commit request is [3]. [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/device-mapper/cache.txt [2] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/device-mapper/cache-policies.txt [3] http://www.mail-archive.com/stable@vger.kernel.org/msg33526.html STEC guyes has try to merge EnhanceIO to upstream[4], but it had not been accepted. [4] http://lwn.net/Articles/536018/ > >> which can be used >> to replace EnahnceIO/flashcache/bcache(IMO). > > IMHO bcache will never be a viable option due to maintenance overhead of > custom patched kernel and (more important) because bcache require special > preparation/formatting of block devices and therefore can't be plugged to > existing file systems with data. > > I see that flashcache matured since 2011 and these days it doesn't cripple > performance-wise as it used to. > > EnhancIO is just fantastic and (hopefully) immediately useful. Package is > ready and only lacking reasonable testing so you're very welcome to try it. :) > > > Regards, > Dmitry Smirnov > GPG key : 4096R/53968D1B I have a brief look at the enhanceIO package, and have some suggestion: 1) Keep EnhanceIO source code in package VCS, this will simplify the build procedure. 2) debian/patches/* is good cadidate for upstream, please don't keep them in debian only. 3) README.Debian looks not debian specific, maybe a simple HOWTO for upstream is better. Thanks, -- Liang Guo http://bluestone.cublog.cn -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
