fio:tldr:ff313

This command is using the fio tool with sudo (superuser do) privileges to run a benchmark test on a file.

Let's break down each option and parameter used in the command:

• --filename=${filename}: Specifies the path and name of the file on which the benchmark test will be performed. The ${filename} is likely a placeholder that needs to be replaced with an actual file name.
• --direct=1: Enables direct I/O, bypassing the operating system cache, to perform the test.
• --rw=randread: Specifies that the I/O workload for the test will be random reads.
• --bs=4k: Sets the block size for each I/O operation to 4 kilobytes.
• --ioengine=libaio: Selects the I/O engine to be used for the test. In this case, libaio is selected, which is a Linux asynchronous I/O access library.
• --iodepth=256: Sets the I/O depth to 256, which determines the amount of outstanding I/O operations at a given time.
• --runtime=120: Sets the duration of the benchmark test to 120 seconds.
• --numjobs=4: Specifies the number of threads or jobs that will be simultaneously executing I/O operations.
• --time_based: Indicates that the test will be time-based, meaning the duration (--runtime) defines when the test will end.
• --group_reporting: Combines the outputs of all jobs into a single report.
• --name=${job_name}: Specifies a name for the job. The ${job_name} is likely another placeholder that should be replaced.
• --eta-newline=1: Prints the estimated completion time (ETA) of the test on a new line.
• --readonly: Restricts the test to only perform read operations, ensuring the data in the file is not modified during the test.

Overall, this command runs a benchmark test on a file using fio with specific settings for random reads, direct I/O, block size, I/O engine, I/O depth, duration, number of jobs, and job name. The sudo command grants the necessary privileges to run the benchmark test.