Hi all,
I’m trying to setup bcache on my system but am failing to attach the cache to the backing device, to make things worse I’m also not able to make any changes to the config.
I’m using this as a guide: wiki archlinux bcache
(I’m not allowed to include links)
The setup:
OS: Manjaro Gnome (fully updated)
Caching device: 2 x 256GB (sdb & sdc) SSD partitioned to partitions of 220 GB (sdb1 & sdc1) configured in software RAID 0 (md0)
(software RAID 0 is confirmed working and performing as expected)
Backing device: 6TB spinning HDD, for testing purposed currently using a 3TB partition (sda1)
OS disk: 256GB Nvme SSD
lsblk output:
[kenneth-Manjaro block]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 65,1M 1 loop /var/lib/snapd/snap/gtk-common-themes/1515
loop1 7:1 0 85M 1 loop /var/lib/snapd/snap/netflix-viewer/18
loop2 7:2 0 55,4M 1 loop /var/lib/snapd/snap/core18/2074
loop3 7:3 0 219M 1 loop /var/lib/snapd/snap/gnome-3-34-1804/72
loop4 7:4 0 32,3M 1 loop /var/lib/snapd/snap/snapd/12883
loop5 7:5 0 32,3M 1 loop /var/lib/snapd/snap/snapd/12704
loop6 7:6 0 55,4M 1 loop /var/lib/snapd/snap/core18/2128
sda 8:0 0 5,5T 0 disk
├─sda1 8:1 0 3T 0 part
│ └─bcache0 253:0 0 3T 0 disk
└─sda3 8:3 0 2,5T 0 part /mnt/LINUX
sdb 8:16 0 238,5G 0 disk
└─sdb1 8:17 0 214,8G 0 part
└─md0 9:0 0 429,4G 0 raid0
sdc 8:32 0 232,9G 0 disk
└─sdc1 8:33 0 214,8G 0 part
└─md0 9:0 0 429,4G 0 raid0
sde 8:64 1 0B 0 disk
sdf 8:80 1 0B 0 disk
sdg 8:96 1 0B 0 disk
sdh 8:112 1 0B 0 disk
sdi 8:128 1 0B 0 disk
nvme0n1 259:0 0 238,5G 0 disk
├─nvme0n1p1 259:1 0 300M 0 part /boot/efi
└─nvme0n1p2 259:2 0 238,2G 0 part /
Backing device Bcache info:
sb.magic ok
sb.first_sector 8 [match]
sb.csum 521FAD0D3B5D31E7 [match]
sb.version 1 [backing device]
dev.label (empty)
dev.uuid 460c8d63-63fe-43ee-b791-2e498382e178
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.data.first_sector 16
dev.data.cache_mode 0 [writethrough]
dev.data.cache_state 0 [detached]
cset.uuid d248c692-0e7a-4ac3-b241-f6bec916918d
Caching device Bcache info:
sb.magic ok
sb.first_sector 8 [match]
sb.csum 20ADC9AA9B637741 [match]
sb.version 3 [cache device]
dev.label (empty)
dev.uuid 374db30d-6420-4059-b117-936a12ea408a
dev.sectors_per_block 8
dev.sectors_per_bucket 4096
dev.cache.first_sector 4096
dev.cache.cache_sectors 900587520
dev.cache.total_sectors 900591616
dev.cache.ordered yes
dev.cache.discard no
dev.cache.pos 0
dev.cache.replacement 0 [lru]
cset.uuid 662f82bb-5dea-4e59-b514-fea2870ea56b
THE PROBLEM(S):
So, everything until this step worked fine:
echo 662f82bb-5dea-4e59-b514-fea2870ea56b > /sys/block/bcache0/bcache/attach
When executing this command (as root) I currently get this:
[kenneth-Manjaro block]# echo 662f82bb-5dea-4e59-b514-fea2870ea56b > /sys/block/bcache0/bcache/attach
bash: echo: write error: Invalid argument
When trying to stop Bcache I get a permission denied, even whilst being root.
[kenneth-Manjaro block]# echo 1 > /sys/block/md0/bcache/stop
bash: /sys/block/md0/bcache/stop: Permission denied
Yet I’m clearly root:
[kenneth-Manjaro block]# whoami
root
[kenneth-Manjaro block]#
So now I’m left with a non-working Bcache setup and there appears to be nothing I can do to resolve it.
Can someone please shed some light on this and help me fix it?
MANY THANKS!