Re: USB upgrade fun

[Satoru Takeuchi <satoru.takeuchi@gmail.com>]

At Sun, 08 Oct 2017 17:58:10 +0800,
Kai Hendry wrote:
> 
> Hi there,
> 
> My /mnt/raid1 suddenly became full somewhat expectedly, so I bought 2
> new USB 4TB hard drives (one WD, one Seagate) to upgrade to.
> 
> After adding sde and sdd I started to see errors in dmesg [2].
> https://s.natalian.org/2017-10-07/raid1-newdisks.txt
> [2] https://s.natalian.org/2017-10-07/btrfs-errors.txt

These messages are harmless. Qu is tuckling on this problem.

> 
> Sidenote: I've since learnt that removing a drive actually deletes the
> contents of the drive? I don't want that. I was hoping to put that drive
> into cold storage. How do I remove a drive without losing data from a
> RAID1 configuration?

Please let me clarify what you said. Do you worry about losing filesystem data
in removed device, in this case /dev/sdc1? To be more specific,
if /mnt/raid1/file is in /dev/sdc1 and lose this file by removing this device?
If so, don't worry. When removing /dev/sdc1, the filesystem data exists in this
device is moved to other devices, /dev/sdb1, /dev/sdd1, or /dev/sde1.

Just FYI, `btrfs replace /dev/sdc1 /dev/sdd1 /mnt/raid1` is more suitable
in your case.

> 
> 
> I assumed it had to perhaps with the USB bus on my NUC5CPYB being maxed
> out, and to expedite the sync, I tried to remove one of the older 2TB
> sdc1.  However the load went crazy and my system went completely
> unstable. I shutdown the machine and after an hour I hard powered it
> down since it seemed to hang (it's headless).

Because all data in /dev/sdc1, in this case totally

 1.81TiB(data) + 6.00GiB(metadata) + 32MiB(system)

should be moved to remaining devices.

> 
> 
> After a reboot it failed, namely because "nofail" wasn't in my fstab and
> systemd is pedantic by default. After managing to get it booting into my
> system without /mnt/raid1 I faced these "open ctree failed" issues. 
> After running btrfs check on all the drives and getting nowhere, I
> decided to unplug the new drives and I discovered that when I take out
> the new 4TB WD drive, I could mount it with -o degraded.
> 
> dmesg errors with the WD include "My Passport" Wrong diagnostic page;
> asked for 1 got 8 "Failed to get diagnostic page 0xffffffea" which
> raised my suspicions. The model number btw is WDBYFT0040BYI-WESN
> 
> Anyway, I'm back up and running with 2x2TB  (one of them didn't finish
> removing, I don't know which) & 1x4TB.
> 
> [1] https://s.natalian.org/2017-10-08/usb-btrfs.txt
> 
> I've decided to send the WD back for a refund. I've decided I want keep
> the 2x2TB and RAID1 with the new 1x4TB disk. So 4TB total. btrfs
> complains now of "Some devices missing" [1]. How do I fix this
> situation?

Probably `btrfs device remove missing /mnt/raid1` works.

Thanks,
Satoru

> 
> Any tips how to name this individual disks? hdparm -I isn't a lot to go
> on.
> 
> [hendry@nuc ~]$ sudo hdparm -I /dev/sdb1 | grep Model
>         Model Number:       ST4000LM024-2AN17V
> [hendry@nuc ~]$ sudo hdparm -I /dev/sdc1 | grep Model
>         Model Number:       ST2000LM003 HN-M201RAD
> [hendry@nuc ~]$ sudo hdparm -I /dev/sdd1 | grep Model
>         Model Number:       ST2000LM005 HN-M201AAD
> 
> 
> Ok, thanks. Hope you can guide me,
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