freebsd-nq/include/linux
Brian Behlendorf 2404b01499 Improve AF hard disk detection
Use the bdev_physical_block_size() interface to determine the
minimize write size which can be issued without incurring a
read-modify-write operation.  This is used to set the ashift
correctly to prevent a performance penalty when using AF hard
disks.

Unfortunately, this interface isn't entirely reliable because
it's not uncommon for disks to misreport this value.  For this
reason you may still need to manually set your ashift with:

  zpool create -o ashift=12 ...

The solution to this in the upstream Illumos source was to add
a white list of known offending drives.  Maintaining such a list
will be a burden, but it still may be worth doing if we can
detect a large number of these drives.  This should be considered
as future work.

Reported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #916
2012-11-15 11:06:14 -08:00
..
blkdev_compat.h Improve AF hard disk detection 2012-11-15 11:06:14 -08:00
dcache_compat.h Linux 3.4 compat, d_make_root() replaces d_alloc_root() 2012-06-11 10:04:49 -07:00
Makefile.am Add the release component to headers 2012-01-18 12:19:47 -08:00
vfs_compat.h Linux 3.6 compat, iops->mkdir() 2012-10-14 15:29:26 -07:00
xattr_compat.h Linux compat 2.6.39: security_inode_init_security() 2011-07-01 12:40:08 -07:00