What I want to achive is that I want to add the problematic disk as raid1 and see how/when it fails and how BTRFS recovers these fails. While the party goes on, the main system shouldn't be interrupted since this is a production system. For example, I would never expect to be ended up with such a readonly state while trying to add a disk with "unknown health" to the system. Was it somewhat expected?
Although we know that disk is about to fail, it still survives. Shouldn't we expect in such a scenario that when system tries to read or write some data from/to that BROKEN_DISK and when it recognizes it failed, it will try to recover the part of the data from GOOD_DISK and try to store that recovered data in some other part of the BROKEN_DISK? Or did I misunderstood the whole thing? Chris Murphy <li...@colorremedies.com>, 29 Ağu 2018 Çar, 00:07 tarihinde şunu yazdı: > > On Tue, Aug 28, 2018 at 12:50 PM, Cerem Cem ASLAN <cerem...@ceremcem.net> > wrote: > > I've successfully moved everything to another disk. (The only hard > > part was configuring the kernel parameters, as my root partition was > > on LVM which is on LUKS partition. Here are the notes, if anyone > > needs: > > https://github.com/ceremcem/smith-sync/blob/master/create-bootable-backup.md) > > > > Now I'm seekin for trouble :) I tried to convert my new system (booted > > with new disk) into raid1 coupled with the problematic old disk. To do > > so, I issued: > > > > sudo btrfs device add /dev/mapper/master-root /mnt/peynir/ > > /dev/mapper/master-root appears to contain an existing filesystem (btrfs). > > ERROR: use the -f option to force overwrite of /dev/mapper/master-root > > aea@aea3:/mnt$ sudo btrfs device add /dev/mapper/master-root /mnt/peynir/ -f > > ERROR: error adding device '/dev/mapper/master-root': Input/output error > > aea@aea3:/mnt$ sudo btrfs device add /dev/mapper/master-root /mnt/peynir/ > > sudo: unable to open /var/lib/sudo/ts/aea: Read-only file system > > > > Now I ended up with a readonly file system. Isn't it possible to add a > > device to a running system? > > Yes. > > The problem is the 2nd error message: > > ERROR: error adding device '/dev/mapper/master-root': Input/output error > > So you need to look in dmesg to see what Btrfs kernel messages > occurred at that time. I'm gonna guess it's a failed write. You have a > few of those in the smartctl log output. Any time a write failure > happens, the operation is always fatal regardless of the file system. > > > > -- > Chris Murphy
