On Fri, Aug 19, 2016 at 08:07:31PM +0200, marcin@mejor.pl wrote:

Hi!
I'm spamming here with simple questions because it looks that documentation
doesn't follow current state of bcachefs.

I've upgraded bcache-tools to b0f08fc1e30daafb274181234dae3408fb2eb69b and
linux-bcache to 9c79c00b0d02f0da5e01ad5cd1bf4ae2ce421d5d.
And now...

1. How to create simple bcachefs on one disk, without any cache?
# ./bcache format --meta_replicas=2 /dev/sdd1
Please supply a device

Help displays:
 # ./bcache format --help
Usage: bcache format [OPTION]... <list of devices>
Create a new bcache volume from one or more devices

Options:
  -C, --cache=dev             Format a cache device
  -w, --block=size            block size
  -n, --btree_node=size       Btree node size, default 256k
      --metadata_csum_type=(none|crc32c|crc64)
                              Checksum type
      --data_csum_type=(none|crc32c|crc64)
                              Checksum type
      --compression_type=(none|gzip)
                              Compression type
      --encrypted             enable encryption
      --meta_replicas=#       number of metadata replicas
      --data_replicas=#       number of data replicas
      --error_action=(continue|readonly|panic)
                              Action to take on filesystem error
  -l, --label=label           label
      --uuid=uuid             filesystem UUID
      --fs_size=size          Size of filesystem on device
  -b, --bucket=size           bucket size
  -t, --tier=#                tier of subsequent devices
      --discard               Enable discards
  -q, --quiet                 reduce output to errors only
  -v, --verbose               increase output to include informational
messages
      --help                  display this help and exit
      --version               output version information and exit

Report bugs to [off-list ref]

I don't know what is correct syntax to format block device.

2. How to create and mount bcachefs witch cache device?
# ./bcache format --compression_type=lz4  --meta_replicas=2 /dev/sdd1  -C
/dev/sde1

Hey, sorry for the long delay, been sick past several days. The way arguments
were passed to bcache format was a holdover from old style make-bcache, and
didn't make much sense for bcachefs - -C was used for all devices, and --tier
specifies fast devices and slow devices.

I finally got around to redoing the option parsing so we don't need the -C
argument today - update your bcache tools, and the command you want is now:

bcache format --tier 0 /dev/sde1 --tier 1 /dev/sdd1

(assuming sde1 is your fast device and sdd1 is your slow device).

Replication is not yet supported (it's around 90% implemented, but I haven't
worked on it in ages and the tests haven't been covering it so you'll likely hit
bugs if you try it).

Compression still isn't _quite_ done, I reverted the accounting until I fix an
issue with copygc. You can enable it and nothing will break, but it won't
actually let you store more data in your fs than if it was uncompressed.