blkdiscard(8) [centos man page]

BLKDISCARD(8)						       System Administration						     BLKDISCARD(8)

NAME

       blkdiscard - discard sectors on a device

SYNOPSIS

       blkdiscard [-o offset] [-l length] [-s] [-v] device

DESCRIPTION

       blkdiscard  is  used  to  discard  device  sectors.   This is useful for solid-state drivers (SSDs) and thinly-provisioned storage.  Unlike
       fstrim(8) this command is used directly on the block device.

       By default, blkdiscard will discard all blocks on the device.  Options may be used to modify this behavior  based  on  range  or  size,	as
       explained below.

       The device argument is the pathname of the block device.

       WARNING: All data in the discarded region on the device will be lost!

OPTIONS

       The  offset  and length arguments may be followed by the multiplicative suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB,
       ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB=1000, MB=1000*1000, and so on  for  GB,  TB,
       PB, EB, ZB and YB.

       -h, --help
	      Print help and exit.

       -o, --offset offset
	      Byte offset in the device from which to discard.	Provided value will be aligned to the device sector size.  Default value is zero.

       -l, --length length
	      Number  of bytes after starting point to discard.  Provided value will be aligned to the device sector size.  If the specified value
	      extends past the end of the device, blkdiscard will stop at the device size boundary.  Default value  extends  to  the  end  of  the
	      device.

       -s, --secure
	      Perform secure discard.  Secure discard is the same as regular discard except all copies of the discarded blocks possibly created by
	      garbage collection must also be erased.  It has to be supported by the device.

       -v, --verbose
	      Print aligned offset and length arguments.

AUTHOR

       Lukas Czerner <lczerner@redhat.com>

SEE ALSO

       fstrim(8)

AVAILABILITY

       The blkdiscard command is part of the util-linux package and is available Linux Kernel Archive  <ftp://ftp.kernel.org/pub/linux/utils/util-
       linux/>.

util-linux							   October 2012 						     BLKDISCARD(8)

Check Out this Related Man Page

FALLOCATE(1)							   User Commands						      FALLOCATE(1)

NAME

       fallocate - preallocate space to a file

SYNOPSIS

       fallocate [-n] [-p] [-o offset] -l length filename

DESCRIPTION

       fallocate  is used to preallocate blocks to a file.  For filesystems which support the fallocate system call, this is done quickly by allo-
       cating blocks and marking them as uninitialized, requiring no IO to the data blocks.  This is much faster than creating a file  by  filling
       it with zeros.

       As of the Linux Kernel v2.6.31, the fallocate system call is supported by the btrfs, ext4, ocfs2, and xfs filesystems.

       The exit code returned by fallocate is 0 on success and 1 on failure.

OPTIONS

       The  length  and offset arguments may be followed by the multiplicative suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB,
       ZiB and YiB (the "iB" is optional, e.g. "K" has the same meaning as "KiB") or the suffixes KB=1000, MB=1000*1000, and so on for GB, TB, PB,
       EB, ZB and YB.

       -n, --keep-size
	      Do not modify the apparent length of the file.  This may effectively allocate blocks past EOF, which can be removed with a truncate.

       -p, --punch-hole
	      Punch holes in the file, the range should not exceed the length of the file.

       -o, --offset offset
	      Specifies the beginning offset of the allocation, in bytes.

       -l, --length length
	      Specifies the length of the allocation, in bytes.

       -h, --help
	      Print help and exit.

       -V, --version
	      Print version and exit.

AUTHORS

       Eric Sandeen <sandeen@redhat.com>
       Karel Zak <kzak@redhat.com>

SEE ALSO

       fallocate(2), posix_fallocate(3), truncate(1)

AVAILABILITY

       The  fallocate  command	is part of the util-linux package and is available from Linux Kernel Archive <ftp://ftp.kernel.org/pub/linux/utils
       /util-linux/>.

util-linux							  September 2011						      FALLOCATE(1)

Linux and UNIX Man Pages

blkdiscard(8) [centos man page]

Check Out this Related Man Page