On Sun, Jan 7, 2018 at 3:03 AM, Oleg Kolosov <olekol@xxxxxxxxx> wrote: > Hi > I was wondering if it's possible to read a single shard in an erasure code? > > I saw this was implemented in Luminous: > > core: osd/ECTransaction: only read partial stripes when below > *original* object size (issue#19882, pr#15712, Sage Weil) > > If yes, how can it be done? no, i don't think so. stripe and shard are different concepts in Ceph. please see http://docs.ceph.com/docs/master/dev/osd_internals/erasure_coding/#glossary . here i assume that what you want to read is strips from a certain shard. but what the change tried to accomplish is to avoid reading beyond original size if a write request touches the area out of the original end of file. it has nothing to do with shard, IMO. -- Regards Kefu Chai -- 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
