Section (8) blkdiscard
blkdiscard — discard sectors on a device
blkdiscard [options] [
−o offset ] [
−l length ] device
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.
argument is the pathname of the block device.
WARNING: All data in the discarded region on the device will be lost!
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.
Byte offset into the device from which to start discarding. The provided value will be aligned to the device sector size. The default value is zero.
The number of bytes to discard (counting from the starting point). The 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. The default value extends to the end of the device.
The number of bytes to discard within one iteration. The default is to discard all by one ioctl call.
Perform a secure discard. A secure discard is the same as a regular discard except that all copies of the discarded blocks that were possibly created by garbage collection must also be erased. This requires support from the device.
Zero-fill rather than discard.
Display the aligned values of
length. If the
−−stepoption is specified, it prints the discard progress every second.
Display version information and exit.
Display help text and exit.
The blkdiscard command is part of the util-linux package and is available Linux Kernel Archive