blkdiscard

blkdiscard [OPTIONS] device

blkdiscard sends TRIM/DISCARD commands to a block device to mark sectors as unused. Unlike fstrim(8), it operates directly on the block device rather than a mounted filesystem. This is particularly useful for SSDs and thinly-provisioned storage. All data in the discarded region will be lost.

-o, --offset offset

Byte offset into the device to start discarding. Must be aligned to the device sector size. Default is 0.

Number of bytes to discard from the offset. Must be aligned to the device sector size.

Discard this many bytes per iteration instead of all at once. Useful for avoiding long uninterruptible operations on large devices.

Perform a secure discard. This tells the device to also erase any copies of the discarded data (e.g. in garbage collection). Requires device support.

Zero-fill the specified region rather than discarding it.

Disable exclusive-open check, allowing operation on mounted devices. Use with caution.

Suppress warning messages.

Print aligned offset and length values and progress information.

This operation destroys data and is irreversible. All data in the discarded region is lost. Not all devices support discard operations; on unsupported devices, blkdiscard exits with status 2 (since util-linux 2.39). Secure discard requires explicit hardware support and may not provide stronger guarantees than regular discard on all devices.

blkdiscard is part of the util-linux package, providing SSD optimization and secure erase functionality.

fstrim(8), hdparm(8), wipefs(8), blkid(8)