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BLOCKDEV(8)		     System Administration		   BLOCKDEV(8)

       blockdev - call block device ioctls from the command line

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

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

       -V     Print version and exit.

       -q     Be quiet.

       -v     Be verbose.

	      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.

       It is possible to give multiple devices and multiple commands.

	      Flush buffers.

	      Get alignment offset.

	      Print blocksize in bytes.

	      Get discard zeroes support status.

	      Get filesystem readahead in 512-byte sectors.

	      Get minimum I/O size.

	      Get optimal I/O size.

	      Get max sectors per request

	      Get physical block (sector) size.

	      Print readahead (in 512-byte sectors).

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

	      Print device size in bytes.

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

	      Print sectorsize in bytes - usually 512.

	      Get size in 512-byte sectors.

	      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).

	      Set read-only.

	      Set read-write.

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

       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)