From mboxrd@z Thu Jan  1 00:00:00 1970
From: marcin@mejor.pl
Subject: Re: How to create bcachefs?
Date: Wed, 24 Aug 2016 23:21:02 +0200
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W dniu 24.08.2016 o 08:52, Kent Overstreet pisze:
[...]

Hi!
> Hey, sorry for the long delay, been sick past several days.

I was afraid that I'm asking to easy question:) And I hope everything is
fine with you now!


> 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).

Does it means that cache is unavailable and only tiering will be in 
bcachefs?
And... How to mount tiered FS? When I pass one device in mount I'm 
getting:
  bcache: bch_open_as_blockdevs() register_cache_set err insufficient 
devices


> 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).

If you tell me how to turn it on I'll try it. In latest bcache-tools
this option disappeared. Turning on using `echo 2 > 
/sys/fs/bcache/<uid>/options/{data_replicas,metadata_replicas}` doesn't 
work.

> 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.


What means option in /sys/fs/..../options/posix_acl? I've got zero value 
but setfacl and getfacl shows that acl works (in theory, I didn't check 
if ACL really works).

I also have feature request: it would be nice to see which file (with 
path) has
checksum error, now it looks like this:
Aug 24 17:15:23 localhost kernel: [ 4692.929060] bcache (dm-10): IO
error on dm-10 for checksum error

I can't help with writing code but I can try to help testing bcachefs. 
I'm especially interested in using:
- cache
- tiering
- compression
- erasure encoding (I know that it isn't started)



Thank you,
Marcin