On Tue, Sep 08, 2015 at 02:17:55PM -0600, Chris Murphy wrote: > On Tue, Sep 8, 2015 at 2:13 PM, Ian Kumlien <ian.kuml...@gmail.com> wrote: > > On 8 September 2015 at 22:08, Chris Murphy <li...@colorremedies.com> wrote: > >> On Tue, Sep 8, 2015 at 2:00 PM, Ian Kumlien <ian.kuml...@gmail.com> wrote: > > > > [--8<--] > > > >>> Someone thought they were done too early, only one disk => read only > >>> mount. But, readonly mount => no balance. > >>> > >>> I think something is wrong.... > >>> > >>> btrfs balance start -dconvert=single -mconvert=single /mnt/disk/ > >>> ERROR: error during balancing '/mnt/disk/' - Read-only file system > >>> > >>> btrfs dev delete missing /mnt/disk/ > >>> ERROR: error removing the device 'missing' - Read-only file system > >>> > >>> Any mount without ro becomes: > >>> [ 507.236652] BTRFS info (device sda2): allowing degraded mounts > >>> [ 507.236655] BTRFS info (device sda2): disk space caching is enabled > >>> [ 507.325365] BTRFS: bdev (null) errs: wr 2036894, rd 2031380, flush > >>> 705, corrupt 0, gen 0 > >>> [ 510.983321] BTRFS: too many missing devices, writeable mount is not > >>> allowed > >>> [ 511.006241] BTRFS: open_ctree failed > >>> > >>> And one of them has to give! ;) > >> > >> > >> You've run into this: > >> https://bugzilla.kernel.org/show_bug.cgi?id=92641 > > > > Ah, I thought it might not be known - I'm currently copying the files > > since a read only mount is "good enough" for that > > > > -o degraded should allow readwrite *IF* the data can be written to.... > > My question is also, would this keep me from "adding devices"? > > I mean, it did seem like a catch 22 earlier, but that would really > > make a mess of things... > > It is not possible to add a device to an ro filesystem, so effectively > the fs read-writeability is broken in this case.
I thought this particular issue had already been dealt with in 4.2? (i.e. you can still mount an FS RW if it's degraded, but there are still some single chunks on it). Ian: If you can still mount the FS read/write with both devices in it, then it might be worth trying to balance away the problematic single chunks with: btrfs bal start -dprofiles=single -mprofiles=single /mountpoint Then unmount, pull the dead drive, and remount -odegraded. Hugo. -- Hugo Mills | The early bird gets the worm, but the second mouse hugo@... carfax.org.uk | gets the cheese. http://carfax.org.uk/ | PGP: E2AB1DE4 |
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