FreeNAS Code

Raise default blocksize and fragment size to 32K and 4K.

Quote from Kirk McKusick:

Raise the default blocksize for UFS/FFS filesystems from
16K to 32K and the default fragment size from 2K to 4K.

The rational is that most disks are now running with 4K
sectors. While they can (slowly) simulate 512-byte sectors
by doing a read-modify-write, it is desirable to avoid this
functionality. By raising the minimum filesystem allocation
to 4K, the filesystem will never trigger the small sector
emulation.

Also, the growth of disk sizes has lead us to double the
default block size about every ten years. The rise from 8K
to 16K blocks was done in 2001. So, by the 10-year metric,
the time has come for 32K blocks.

Discussed at: May 2011 BSDCan Developer Summit
Reference: http://wiki.freebsd.org/201105DevSummit/FileSystems