A small amount of backstory:
I have a small media filesystem, on which I store various movies and TV shows that are used for my HTPC setup. This was originally set up, using
btrfs, on a 1TB WD external drive.
Later, I decided to purchase another drive, to give this filesystem RAID1 mirroring capabilities. This drive is a Seagate Barracuda (2TB, BARRACUDA 7200.14 FAMILY). Unfortunately, this was not a good choice of drive. The drive started developing large amounts of read errors shortly, although BTRFS was able to correct them.
Recently, the amount of read errors from this drive has spiked, with its condition steadily worsening. BTRFS is now starting to crash:
kernel: RSP: 0018:ffff88005f0e7cc0 EFLAGS: 00010282 kernel: RIP: 0010:[<ffffffffa0081736>] [<ffffffffa0081736>] btrfs_check_repairable+0xf6/0x100 [btrfs] kernel: task: ffff88001b5c4740 ti: ffff88005f0e4000 task.ti: ffff88005f0e4000 kernel: Workqueue: btrfs-endio btrfs_endio_helper [btrfs] kernel: CPU: 1 PID: 3136 Comm: kworker/u8:3 Tainted: G O 4.5.3-1-ARCH #1 kernel: invalid opcode: 0000 [#1] PREEMPT SMP kernel: kernel BUG at fs/btrfs/extent_io.c:2309! kernel: ------------[ cut here ]------------ kernel: BTRFS info (device sdc1): csum failed ino 73072 extent 1531717287936 csum 3335082470 wanted 3200325796 mirror 0 kernel: ata3: EH complete kernel: BTRFS error (device sdc1): bdev /dev/sda3 errs: wr 0, rd 18, flush 0, corrupt 0, gen 0 kernel: blk_update_request: I/O error, dev sda, sector 2991635296
I'd like to remove the faulty drive from the RAID1 array, going back to no redundancy on a single drive. Unfortunately, there seems to be a lack of documentation on how to do this.
I am aware that one can run the following:
sudo btrfs balance start -dconvert=single /media
to convert the data profile to
single mode, but I'm unsure as to just WHERE the data will be placed. As one of the drives is failing, I'd like to be able to ensure that BTRFS doesn't dutifully erase all the data on the good drive, and place a single copy on the bad drive - instead, I'd like to simply act as if the other drive never existed (as in, convert back to my old setup)
This doesn't work:
$ sudo btrfs device delete /dev/sda3 /media ERROR: error removing device '/dev/sda3': unable to go below two devices on raid1
What am I to do? Help would be greatly appreciated.
TL;DR: started with 1 drive in BTRFS
single, added another drive, made it
RAID1, other drive is now erroring, how do I return to just one drive (SPECIFICALLY the known good one) with