Am 10.02.20 um 01:22 schrieb Chris Murphy:
You might just go straight to ARM, and try to mount -o ro and see if it mounts it OK. I think the error messages you got from Btrfs previously had to do with the bogus GPT error messages - which we don't know why that happened.
Unfortunately it still does not mount: mount -o ro /dev/disk/by-label/URAID /mnt/URAID/ mount: /mnt/URAID: wrong fs type, bad option, bad superblock on /dev/sdb1, missing codepage or helper program, or other error. [ 182.039688] usb 2-2: new SuperSpeed Gen 1 USB device number 2 using xhci_hcd [ 182.071047] usb 2-2: New USB device found, idVendor=152d, idProduct=0567, bcdDevice=52.03 [ 182.071063] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 182.071076] usb 2-2: Product: External USB 3.0 [ 182.071089] usb 2-2: Manufacturer: JMicron [ 182.071101] usb 2-2: SerialNumber: 20170331000C3 [ 182.074585] usb-storage 2-2:1.0: USB Mass Storage device detected [ 182.079212] usb-storage 2-2:1.0: Quirks match for vid 152d pid 0567: 5000000 [ 182.079424] scsi host0: usb-storage 2-2:1.0 [ 183.130129] scsi 0:0:0:0: Direct-Access External USB3.0 DISK03 5203 PQ: 0 ANSI: 6 [ 183.131024] sd 0:0:0:0: [sda] Very big device. Trying to use READ CAPACITY(16). [ 183.131252] sd 0:0:0:0: [sda] 7814037168 512-byte logical blocks: (4.00 TB/3.64 TiB) [ 183.131267] sd 0:0:0:0: [sda] 4096-byte physical blocks [ 183.131904] sd 0:0:0:0: [sda] Write Protect is off [ 183.131919] sd 0:0:0:0: [sda] Mode Sense: 2b 00 00 00 [ 183.132258] scsi 0:0:0:1: Direct-Access External USB3.0 DISK04 5203 PQ: 0 ANSI: 6 [ 183.139512] sd 0:0:0:0: [sda] No Caching mode page found [ 183.139528] sd 0:0:0:0: [sda] Assuming drive cache: write through [ 183.140186] sd 0:0:0:1: [sdb] Very big device. Trying to use READ CAPACITY(16). [ 183.140467] sd 0:0:0:1: [sdb] 7814037168 512-byte logical blocks: (4.00 TB/3.64 TiB) [ 183.140483] sd 0:0:0:1: [sdb] 4096-byte physical blocks [ 183.141135] sd 0:0:0:1: [sdb] Write Protect is off [ 183.141151] sd 0:0:0:1: [sdb] Mode Sense: 2b 00 00 00 [ 183.142195] sd 0:0:0:1: [sdb] No Caching mode page found [ 183.142211] sd 0:0:0:1: [sdb] Assuming drive cache: write through [ 183.151939] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 183.152161] sd 0:0:0:1: Attached scsi generic sg1 type 0 [ 183.308231] sdb: sdb1 [ 183.308429] sda: sda1 [ 183.310527] sd 0:0:0:1: [sdb] Attached SCSI disk [ 183.311834] sd 0:0:0:0: [sda] Attached SCSI disk [ 183.572564] BTRFS: device label URAID devid 8 transid 1254643 /dev/sdb1 [ 183.575573] BTRFS: device label URAID devid 7 transid 1254643 /dev/sda1 [ 228.067813] BTRFS info (device sda1): disk space caching is enabled [ 228.067827] BTRFS info (device sda1): has skinny extents [ 228.072861] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.081639] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.090173] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.098571] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.107030] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.115469] BTRFS critical (device sda1): unable to find logical 4306137776128 length 4096 [ 228.123928] BTRFS error (device sda1): failed to read chunk root [ 228.160012] BTRFS error (device sda1): open_ctree failed apt-cache show btrfs-progs | grep Version Version: 4.20.1-2 uname -a Linux omv 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux I'm going to get some large external drives, copy the data and will go back to an old-school software raid. btrfs is not portable in my eyes. When this is happening I would strongly recommend to wait another 5 years before using it anywhere. I'm pretty sure this is not an Arch Linux issue, it might be a raspbian issue.