How to Use dd Command to Test the Hard Disk Speed?

To test the disk speed with the dd command, you can use it to write a temporary file and measure the write and read speeds. Here are examples:

Test Write Speed

This command writes a 1GB file to your disk, providing the write speed:

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dd if=/dev/zero of=testfile bs=1G count=1 oflag=dsync

dd if=/dev/zero of=testfile bs=1G count=1 oflag=dsync

• if=/dev/zero uses a source of empty bytes.
• of=testfile specifies the output file.
• bs=1G sets the block size to 1 GB.
• count=1 specifies to write only one block.
• oflag=dsync ensures data is physically written to disk, giving a more accurate speed measurement.

Example output:

1+0 records in
1+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 1.58025 s, 679 MB/s

Test Read Speed

First, clear the file system cache to avoid caching effects:

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sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'

sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'

Then, read the file back:

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dd if=testfile of=/dev/null bs=1G count=1

dd if=testfile of=/dev/null bs=1G count=1

• if=testfile reads from the file you just wrote.
• of=/dev/null discards the output, ensuring only read speed is tested.

Clean Up

After the test, delete the temporary file:

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rm testfile

rm testfile

These commands provide approximate disk speeds, but for more accurate results, dedicated benchmarking tools like fio or hdparm are recommended.

–EOF (The Ultimate Computing & Technology Blog) —