Hi there,
I planned to remove one of my disks, so that I can take it from
Singapore to the UK and then re-establish another remote RAID1 store.
delete is an alias of remove, so I added a new disk (devid 3) and
proceeded to run:
btrfs device delete /dev/sdc1 /mnt/raid1 (devid 1)
nuc:~$ uname -a
Linux nuc 4.5.4-1-ARCH #1 SMP PREEMPT Wed May 11 22:21:28 CEST 2016
x86_64 GNU/Linux
nuc:~$ btrfs --version
btrfs-progs v4.5.3
nuc:~$ sudo btrfs fi show /mnt/raid1/
Label: 'extraid1' uuid: 5cab2a4a-e282-4931-b178-bec4c73cdf77
Total devices 2 FS bytes used 776.56GiB
devid 2 size 931.48GiB used 778.03GiB path /dev/sdb1
devid 3 size 1.82TiB used 778.03GiB path /dev/sdd1
nuc:~$ sudo btrfs fi df /mnt/raid1/
Data, RAID1: total=775.00GiB, used=774.39GiB
System, RAID1: total=32.00MiB, used=144.00KiB
Metadata, RAID1: total=3.00GiB, used=2.17GiB
GlobalReserve, single: total=512.00MiB, used=0.00B
First off, I was expecting btrfs to release the drive pretty much
immediately. The command took about half a day to complete. I watched
`btrfs fi show` to see size of devid 1 (the one I am trying to remove)
to be zero and to see used space slowly go down whilst used space of
devid 3 (the new disk) slowly go up.
Secondly and most importantly my /dev/sdc1 can't be mounted now anymore.
Why?
sudo mount -t btrfs /dev/sdc1 /mnt/test/
mount: wrong fs type, bad option, bad superblock on /dev/sdc1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
There is nothing in dmesg nor my journal. I wasn't expecting my drive to
be rendered useless on removing or am I missing something?
nuc:~$ sudo fdisk -l /dev/sdc
Disk /dev/sdc: 931.5 GiB, 1000204885504 bytes, 1953525167 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 33553920 bytes
Disklabel type: gpt
Disk identifier: 19938642-3B10-4220-BF99-3E12AF1D1CF6
Device Start End Sectors Size Type
/dev/sdc1 2048 1953525133 1953523086 931.5G Linux filesystem
On #btrfs IRC channel I'm told:
<Knorrie> hendry: breaking multi-disk filesystems in half is not a
recommended way to do "normal operations" :D
I'm still keen to take a TB on a flight with me the day after tomorrow.
What is the recommended course of action? Recreate a mkfs.btrfs on
/dev/sdc1 and send data to it from /mnt/raid1?
Still I hope the experience could be improved to remove a disk sanely.
Many thanks,
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