thin_metadata_size: where do i get block size?

[Harvie]

I am trying to figure out thin pool metadata size, but thin_metadata_size command needs me to enter block size. How do i get this value? Is this block size of harddrive? Is this block size of pool or some other internal LVM stuff? i can't tell from manpage...

Can you please explain this in the manpage (preferably with example command for obtaining that value), so it's clear once and for all? I think that especialy newbies like me are prone to misjudging the metadata size, so this calculator should be as easy as possible to use.

Here are some of my details:

  --- Physical volume ---
  PV Name               /dev/md12
  VG Name               vg_xxx
  PV Size               931.32 GiB / not usable 2.87 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              238416
  Free PE               10426
  Allocated PE          227990
  PV UUID               xxx

  --- Volume group ---
  VG Name               vg_xxx
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  155
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                35
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               931.31 GiB
  PE Size               4.00 MiB
  Total PE              238416
  Alloc PE / Size       227990 / 890.59 GiB
  Free  PE / Size       10426 / 40.73 GiB
  VG UUID               xxxxxxxxxxxxxxxxxxx


  --- Logical volume ---
  LV Path                /dev/vg_xxx/xxx
  LV Name                xxx
  VG Name                vg_xxx
  LV UUID                xxx
  LV Write Access        read/write
  LV Creation host, time xxx, 2013-10-17 21:07:12 +0200
  LV Status              available
  # open                 0
  LV Size                2.73 TiB
  Current LE             715264
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:27

[Harvie]

Also i think there might be simplified mode, where you just enter name of vg/thin-pool and the reccomended metadata size will get figured out automagicaly...