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.

--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/.