This is *not* to install bcache, but to read a bcache backing partition when the cache is no more available.

the manual says:

"make-bcache has the ability to format multiple devices at the same time"

but then:

To get started:

  mkfs.ext4 /dev/bcache0

so the word "format" is not used always with the same meaning (for me, formatting is creating a file system).

gladfully, make-bcache do *not* format the partition.

What I did:

  • install a new system elsewhere (same distro I used with bcache). kernel 3.16.7

install bcache-tools

make-bcache -B /dev/sda8 (the old bcache backing)

tried to find /sys/block/sda/bcache, but it do not exist. Your example made me think the manual lacked a level, it have to be sys/block/sda/sda8/bcache

echo 1 > /sys/block/sda/sda3/bcache/running

and then /dev/bcache0 shows up!

mount /dev/bcache0 /mnt allows me to access the files on the partition

so good, thanks! jdd