On Thu, Sep 29, 2016 at 12:26 AM, Ning Yao <zay11022@xxxxxxxxx> wrote: > Hi, > > As lots of fiemap issues in XFS, fiemap is default disabled now, > especially in Hammer, before seek_data, seek_hole is added. > > But disabling fiemap feature will cause a small sparse object become a > large full object during PushOps, which may lead to notably data > in-balance between OSD, especially on the new added OSD during data > rebalance. With those full objects, some OSDs may simultaneously > becomes full. Until now, I don't know existing problem with fiemap enabled in hammer. Although we find it maybe problem when clone to a existing overlap data range, but it won't exists in real case. > > Furthermore, currently, it is impossible to make the full objects > sparse again if we enable the fiemap feature in the future. > > So I think if any solutions to make a full object back to a sparse > object again? One of the idea is to check whether the content in the > object contains consecutive zero and punch zeros for those object > during deep-scrub, is that possible and reasonable? Obviously it's a complex thing more than we get. > > > > Regards > Ning Yao > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" 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 ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
