BLOCKDEV(8)		     System Administration		   BLOCKDEV(8)



NAME
       blockdev - call block device ioctls from the command line

SYNOPSIS
       blockdev [-q] [-v] command [command...]	device [device...]
       blockdev --report [device...]

DESCRIPTION
       The  utility  blockdev  allows one to call block device ioctls from the
       command line.

OPTIONS
       -V     Print version and exit.

       -q     Be quiet.

       -v     Be verbose.

       --report
	      Print a report for the specified device. It is possible to  give
	      multiple	devices. If none is given, all devices which appear in
	      /proc/partitions are shown. Note that the partition StartSec  is
	      in 512-byte sectors.

COMMANDS
       It is possible to give multiple devices and multiple commands.

       --flushbufs
	      Flush buffers.

       --getalignoff
	      Get alignment offset.

       --getbsz
	      Print blocksize in bytes.

       --getdiscardzeroes
	      Get discard zeroes support status.

       --getfra
	      Get filesystem readahead in 512-byte sectors.

       --getiomin
	      Get minimum I/O size.

       --getioopt
	      Get optimal I/O size.

       --getmaxsect
	      Get max sectors per request

       --getpbsz
	      Get physical block (sector) size.

       --getra
	      Print readahead (in 512-byte sectors).

       --getro
	      Get read-only. Print 1 if the device is read-only, 0 otherwise.

       --getsize64
	      Print device size in bytes.

       --getsize
	      Print  device  size (32-bit!) in sectors. Deprecated in favor of
	      the --getsz option.

       --getss
	      Print sectorsize in bytes - usually 512.

       --getsz
	      Get size in 512-byte sectors.

       --rereadpt
	      Reread partition table

       --setbsz bytes
	      Set blocksize. Note that the block size is specific to the  cur-
	      rent  file descriptor opening the block device, so the change of
	      block size only persists for as long as blockdev has the	device
	      open, and is lost once blockdev exits.

       --setfra sectors
	      Set filesystem readahead (same like --setra on 2.6 kernels).

       --setra sectors
	      Set readahead (in 512-byte sectors).

       --setro
	      Set read-only.

       --setrw
	      Set read-write.

AUTHOR
       blockdev was written by Andries E. Brouwer and rewritten by Karel Zak.

AVAILABILITY
       The blockdev command is part of the util-linux package and is available
       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.




util-linux			  August 2010			   BLOCKDEV(8)