On July 14, 2026 11:21:45 AM GMT+02:00, Stuart Henderson <[email protected]> wrote: >On 2026-07-13, Chris Ross <[email protected]> wrote: >> So, I have a failed disk in a softraid mirror. While looking to replace it, >> I want to just replace both drives and get a larger fs. >> Most of my experience in recent years has been using ZFS, so I know how to >> do exactly this with ZFS. But, I can’t find a general guide or anything >> specific in the docs/pages for bioctl, that describes how to do this with >> OpenBSD. >> >> Is there a way to replace a failed drive with a larger one, rebuild the >> mirror onto it, then replace the smaller remaining drive with one of equal >> size and rebuild onto that? Then, a step would need to be performed to tell >> the softraid device to fill the new available space, and then growfs. >> >> Thanks. Sorry if it is already documented somewhere and I failed to find >> it in my quick search. > >Not supported with softraid. You can't create a "1-disk RAID1" and add >the second drive later either. Unless you want to get dirty with poking >at low level data structures, you'll either need to have both new drives >and the remaining working old drive connected at the same time and >dump/restore, or dump to external media + swap drives + restore, etc.
I don't think the intention is to create a new single-disk RAID1. It sounds more like replacing/rebuilding/"resilver" one underlying disk at a time onto a larger RAID partition and then let the sr disk grow into them, giving free space at the end of it. I would guess it, at least, boils down to: - location of the sr metadata within the underlying RAID partition(s). If it is only at the beginning it's probably easier. - presence of RAID1 disk size in metadata. This might be trickier, but one might be able to force bioctl to reinitialize a larger RAID1 on top of the former. Anyway, this probably shouldn't be attempted if you are not ready to accept losing your data. Even if so, I would recommend trying it out on a smaller scale with some spare drives first. /Alexander
