On Mon, Feb 4, 2019 at 3:19 PM Patrik Lundquist <patrik.lundqu...@gmail.com> wrote: > > On Mon, 4 Feb 2019 at 18:55, Austin S. Hemmelgarn <ahferro...@gmail.com> > wrote: > > > > On 2019-02-04 12:47, Patrik Lundquist wrote: > > > On Sun, 3 Feb 2019 at 01:24, Chris Murphy <li...@colorremedies.com> wrote: > > >> > > >> 1. At least with raid1/10, a particular device can only be mounted > > >> rw,degraded one time and from then on it fails, and can only be ro > > >> mounted. There are patches for this but I don't think they've been > > >> merged still. > > > > > > That should be fixed since Linux 4.14. > > > > > > > Did the patches that fixed chunk generation land too? Last I knew, 4.14 > > had the patch that fixed mounting volumes that had this particular > > issue, but not the patches that prevented a writable degraded mount from > > producing the issue on-disk in the first place. > > A very good question and at least 4.19.12 creates single chunks > instead of raid1 chunks if I rip out one disk of two in a raid1 setup > and mount it degraded. So a balance from single chunks to raid1 chunks > is still needed after the failed device has been replaced.
Kernel 4.20.3 I can confirm that I can do at least three rw,degraded mounts, adding data each mount, on a two device raid1 with a missing device. When rw,degraded, it's writing data to single profile chunks, and to raid1 metadata chunks. There's no warning about this. After remounting both devices and scrubbing, it's dog slow. 14 minutes to scrub a 4GiB file system, complaining the whole time about checksums on the files not replicated. All it appears to be doing is replicating metadata at a snails pace, less than 2MB/s. That's unexpected. But while it's expected single data is not magically converted to raid1; the fact that it's single profile just because it's a degraded raid1 is not expected, and not warned about. I don't like this behavior - so now the user has to do a balance convert to get back to the replicated state they thought they had when formatting? -- Chris Murphy
