On 22 July 2015 at 18:27, Karel Gardas <[email protected]> wrote: > On Wed, Jul 22, 2015 at 6:43 PM, Kenneth Westerback > <[email protected]> wrote: >> On 22 July 2015 at 12:36, Ted Unangst <[email protected]> wrote: >>> Kenneth R Westerback wrote: >>>> CAVEAT: The metadata version has changed so new volumes you create >>>> will not be loadable on boxes running older versions of OpenBSD. >>>> >>>> CAVEAT: You can't rebuild a volume created with *only* 512-byte >>>> devices onto a 4K-sector device. The volume must be created with >>>> at least one 4K device to start with. >>> >>> given these two caveats, is it reasonable to continue using the old metadata >>> format for 512 byte arrays? perhaps for some time anwyay. >> >> I have thought of that. An alternative would be to make all version 6 >> volumes be 4096-byte sector devices and thus eliminate the "can I >> rebuild using this 4K disk or not?" question. > > Great work! I'm curious how complex would be to add support for > rebuild with 4k drive into array with 512b drives so far? The diff > looks like you will need to modify some metadata on 512b drives to > makes sectors look like 4k, but otherwise it does not look like > impossible job.
It is likely to be tricky and not guaranteed to work in all cases. But if everything is aligned compatibly, it might be possible. .... Ken > > I don't mean that as a criticism, I'm glad you have done this job > since it's inspiring for my ongoing "add checksums to SR RAID 1" hobby > task here. While working on this btw, I've been always wondering if > 512b drives are the only supported option or not... > > Thanks! > Karel
