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       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.


              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)

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