NAME | SYNOPSIS | DESCRIPTION | OPTIONS | COMMANDS | AUTHOR | AVAILABILITY | COLOPHON

BLOCKDEV(8)                 System Administration                BLOCKDEV(8)

NAME         top

       blockdev - call block device ioctls from the command line

SYNOPSIS         top

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

DESCRIPTION         top

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

OPTIONS         top

       -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         top

       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 sector size 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
              current 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         top

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

AVAILABILITY         top

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

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2016-08-07.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

util-linux                       August 2010                     BLOCKDEV(8)