On 28/08/2021 19:58, Jingyun He wrote:

Hello, all
I'm new to btrfs, I have a HM-SMR 14TB disk, I have formatted it to
btrfs to store the files.

When the device is almost full, it needs about 5 mins to mount the device.

Is it normal? is there any mount option that I can use to reduce the mount time?

  We need to figure out the function taking a longer time (maybe it is
  read-block-groups). I have similar reports on the non zoned device
  as well (with a few TB full of data). But there is no good data yet
  to analyse.

  Could you please collect the trace data from the ftracegraph
  from here [1] (It needs trace-cmd).

  [1] https://github.com/asj/btrfstrace.git

  Run it as in the example below:

  umount /btrfs;

  ./ftracegraph open_ctree 3 "*:mod:btrfs" "mount /dev/vg/scratch0 /btrfs"

  cat /tmp/ftracegraph.out


Thanks, Anand

Thank you.