「blockdev」-

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blockdev – call block device ioctls from the command line

命令语法格式

blockdev [-q] [-v] command [command…] device [device…]

blockdev –report [device…]

blockdev -h|-V

命令描述

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

命令支持的选项及含义

-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.

-h, –help
Display help text and exit.

-V, –version
Print version and exit.

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 logical 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. The currently active access to the device may not be affected by the change. For example filesystem already mounted in read-write mode will not be affected. The change applies after remount.

–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
https://www.kernel.org/pub/linux/utils/util-linux/.

参考文献

  • man 8 blockdev, Version blockdev from util-linux 2.32

更新日志

  • 07/11/2018 创建文章