Hi, Am 26.09.2014 um 10:02 schrieb Haomai Wang: > If user enable fiemap feature in osd side, there exists three ways to make > read/write sprase: > > 1. normal sparse read/write op > 2. clone op > 3. recover op > > If any op doesn't support sparse way, it will destroy the advantage of this > way and write zero hole to sparse file. Now clone op can support sparse write, > this commit(https://github.com/ceph/ceph/pull/2137) implement sparse > read/write for recover op. > > The main advantage is if rbd usage, it will hugely reduce the actual > capacity usage and will make clone/recovery faster! OK thanks - but how can i check whether fiemap works on 3.10.55? Greets, Stefan > On Fri, Sep 26, 2014 at 3:53 PM, Stefan Priebe - Profihost AG > <s.priebe at profihost.ag> wrote: >> Am 26.09.2014 um 09:36 schrieb Haomai Wang: >>> Sorry, the bug last mail reported exists in centos 6.5. >>> >>> I'm not sure which kernel version solve this bug and 3.12 kernel is >>> safe with fiemap on XFS >> >> What's the advantage of fiemap? I've a vanilla 3.10.55 kernel. >> >> Stefan >> >>> On Fri, Sep 26, 2014 at 3:33 PM, Haomai Wang <haomaiwang at gmail.com> wrote: >>>> On Fri, Sep 26, 2014 at 3:04 PM, Stefan Priebe - Profihost AG >>>> <s.priebe at profihost.ag> wrote: >>>>> Hi, >>>>> >>>>> as the documentation is very unspecific on this option i'm not sure >>>>> whether we should enable or disable this one on dumpling. >>>> >>>> It all depends on your kernel version. For example, as I remember >>>> there exists known XFS fiemap bug which will return false extent map. >>>> >>>> So you must ensure your kernel version with your local filesystem has >>>> the right fiemap impl. >>>> >>>>> >>>>> Greets, >>>>> Stefan >>>>> _______________________________________________ >>>>> ceph-users mailing list >>>>> ceph-users at lists.ceph.com >>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>>> >>>> >>>> >>>> -- >>>> Best Regards, >>>> >>>> Wheat >>> >>> >>> > > >
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