On 20 February 2016 at 10:29, Karel Gardas <gard...@gmail.com> wrote: > scrub is IIRC not supported by any softraid yet. Rebuild by all which > support redundancy. Marcus recommendation to read man pages can just > be highlighted here. Otherwise just read the code for ultimate > reference of what is or is not done.
Scrub cannot possibly be supported due to the design of the softraid: http://mdoc.su/o/softraid.4 >>>> The RAID 1 discipline does not initialize the mirror upon creation. This >>>> is by design because all sectors that are read are written first. There is >>>> no point in wasting a lot of time syncing random data. IIRC, other raid disciplines are not that much different, either. E.g., a scrub implementation would have to be implemented on top of the filesystem, and would have to be able to temporarily force the reads to be done from a certain chunk only. Long-term, it'll probably be easier to re-do the logic to actually zero-out all the unused sectors, if scrub support is deemed important. Which is why things like ZFS are superior due to having the awareness of the underlying storage blocks. C.
