blkrawverify - Linux
Overview
blkrawverify is a utility used to verify raw block devices (e.g., hard drives, SSDs) by comparing their data against a reference image. It’s particularly useful for detecting data corruption or verifying the integrity of cloned or migrated storage devices.
Syntax
blkrawverify [options] <reference> <device>
Options/Flags
- -c, –chunk-size: Set the chunk size (in bytes) for data transfer and verification. Default: 64 KiB
- -m, –md5: Generate an MD5 hash of the device’s data and compare it against the MD5 hash of the reference image.
- –hexdump: Dump the first 1 KiB of mismatched data in hex format.
- –ignore-blocks: Ignore specified range of blocks when verifying. Format: "
: " (e.g., "100:200"). - –offset: Start verifying from the specified byte offset on both the reference image and device.
- –quiet: Suppress progress and only print error messages.
- -h, –help: Display help and usage information.
Examples
Simple Verification:
blkrawverify ref.img /dev/sda
Verification with MD5 Check:
blkrawverify -m ref.img /dev/sdb
Verifying from a Specific Offset:
blkrawverify --offset 1000000000 ref.img /dev/sdc
Ignoring Blocks from Verification:
blkrawverify --ignore-blocks 1000:2000 ref.img /dev/sdd
Common Issues
- Missing Reference Image: Ensure the specified reference image exists and is accessible.
- Permission Errors: Verify that you have read access to the reference image and write access to the device being verified.
- Data Mismatch: If data corruption is detected, compare the reference image and the device at a byte level to identify the corrupted sectors.
Integration
With dd
: Use blkrawverify
to verify the integrity of data cloned using dd
:
dd if=src.img of=dst.img bs=64K conv=sync
blkrawverify src.img dst.img
With rsync
: Verify the integrity of files copied using rsync
:
# Create a reference image of the source directory
rsync -av --files-from=/dev/null /src /ref/
# Copy the files to the destination directory
rsync -av --files-from=/dev/null /src /dst
# Verify the integrity of the copied files
blkrawverify /ref/ /dst
Related Commands
bmaptool
: Manipulate block mappingsdd
: Copy and convert datamd5sum
: Calculate MD5 checksumsrsync
: Remote file copying and synchronization