On Thu, Sep 29, 2016 at 10:25 AM, Haomai Wang <haomai@xxxxxxxx> wrote: > 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. Hmm, I can't guarantee this... I only means if you want to have sparse object, you can enable this. .... > >> >> 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
