Understanding the 'f3write' Command (with examples)
The ‘f3write’ command is an essential tool for anyone who needs to test the real capacity of storage devices. In recent times, counterfeit and misrepresented storage devices have flooded the market. These devices often claim larger than actual capacities, leading to data loss if users happen to exceed the real capacity limits. ‘f3write’ generates and writes test files to completely fill a storage device with known data, allowing users to verify the actual usable space. This facilitates detecting fraudulent devices by giving an accurate depiction of available storage.
Use case 1: Write test files to a given directory, filling the drive
Code:
f3write path/to/mount_point
Motivation:
Understanding the actual storage capacity of a drive is crucial for various reasons. First and foremost, many counterfeit drives advertise false storage capacities, causing considerable inconvenience and data loss. By using ‘f3write’ to fill a drive with test files, users can measure the authentic capacity, ensuring they do not inadvertently surpass it and lose data. This is especially important for professionals dealing with critical data whose loss would have severe consequences.
Explanation:
f3write: This is the command that initiates the process of writing .h2w test files to the specified drive.path/to/mount_point: This argument specifies the directory path of the mounted drive where the test files will be written. It is crucial to ensure that the correct path is specified, as this operation will consume available storage space.
Example Output:
Free space: 15.95 GB
Creating file 1.h2w ... OK!
Creating file 2.h2w ... OK!
...
Creating file 14.h2w ... OK!
Creating file 15.h2w ... OK!
Free space: 0.01 MB
Operation completed successfully.
Here, the output shows that the command has filled the drive, starting with noting the free space and confirming each file creation until the space is exhausted. It confirms the operation’s completion without encountering errors, indicating the drive’s real capacity is approximately the total volume of .h2w files successfully written.
Use case 2: Limit the write speed
Code:
f3write --max-write-rate=kb_per_second path/to/mount_point
Motivation:
Limiting the write speed can be beneficial in situations where maintaining system responsiveness is essential, such as when the drive is being used in a multi-user environment or when system resources are limited. Additionally, it can help prevent overheating of storage devices, particularly SSDs that might degrade in performance with sustained high-speed data writing.
Explanation:
f3write: Initiates the file writing process using the ‘f3write’ command.--max-write-rate=kb_per_second: This option sets a maximum limit on the data writing speed, measured in kilobytes per second. By setting this rate, you can control the drive’s performance to suit system capability or environmental conditions.path/to/mount_point: As previously, this refers to the directory path where the target drive is mounted.
Example Output:
Free space: 20.00 GB
Creating file 1.h2w ... OK! (11234 KB/s)
Creating file 2.h2w ... OK! (11028 KB/s)
...
Creating file 18.h2w ... OK! (11100 KB/s)
Free space: 0.01 MB
Operation completed successfully.
The output here indicates that the writing speed was controlled as per the –max-write-rate parameter, showing each file being written within the limit instead of at maximum possible speed. This ensures less disruption to other processes or reduces wear on the drive.
Conclusion
The ‘f3write’ command is an effective tool for verifying the real storage capacity of a drive, helping users guard against counterfeit devices and potential data loss. By filling the drive with identifiable test files, users can check the actual storage limits. Additionally, by utilizing options to control write speeds, one can optimize performance and maintain system stability during the testing process. Together these functionalities make ‘f3write’ vital for ensuring storage integrity and reliability.
