2016-10-24 19:27 GMT-07:00 kefu chai <tchaikov@xxxxxxxxx>: > posting this to ceph-users mailing list. > > On Tue, Oct 25, 2016 at 2:02 AM, Andrzej Jakowski > <andrzej.jakowski@xxxxxxxxx> wrote: >> Hi, >> >> Wanted to learn more on what is the Ceph community take on the deep >> scrubbing process. >> It seems that deep scrubbing is expected to read data from physical >> media: NAND dies or magnetic platters. >> What in case if OSD is build on top of some kind of volume and the >> logic in the volume manager prevents OSD scrubbing process to read the >> data from physical media? > > so it's a read only media, and read-only only for scrubbing. so you > have no choice but to disable the scrub, i guess? > > $ ceph osd set noscrub > $ ceph osd set nodeep-scrub No, let me rephrase this. We can imagine following situation: Logical volume manager implements some kind of caching. OSD is built on top of the cache volume. If deep scrubbing is done, data may not be read from primary storage but from cache due to cache hit. In case if data is corrupted in the primary storage deep scrubbing may not be detect it. Is there a way for OSD to force reading data from primary storage device? >> >> Thanks! >> Andrzej Jakowski >> -- >> 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 > > > > -- > 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
