On Thu, Aug 25, 2016 at 7:21 AM, marcin@xxxxxxxx wrote:
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
Tiering gets you all the advantages of caching, plus you can (with some
effort) have the combined filesystem size be the sum of the SSD + HDD
capacities, rather than the capacity be determined solely by the
capacity of the slow tier (this is not currently the case for bcachefs).
To mount a tiered FS you can either pass all the relevant devices to
mount, like:
mount -t bcache /dev/sda:/dev/sdb:/dev/sdc /mountpoint
(I haven't tested this recently) or ensure that all the relevant
devices have been registered with bcache, like so:
echo /dev/sda | sudo tee /sys/fs/bcache/register_quiet
echo /dev/sdb | sudo tee /sys/fs/bcache/register_quiet
echo /dev/sdc | sudo tee /sys/fs/bcache/register_quiet
mount -t bcache /dev/sdb /mountpoint
(you can use any member of the set as the device to mount in this case).
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